All questions
Question 1
A Latin student knows the adjective fortis, forte (brave, strong). She wants to form the abstract noun meaning 'bravery' or 'strength' from this root. Which form correctly applies the standard Latin word-family pattern for converting a third-declension adjective into an abstract noun?
- fortitudo, fortitudinis (f.), formed by adding the suffix -tudo to the adjective stem forti-, a pattern that regularly produces abstract nouns of quality from adjective stems (cf. magnitudo from magnus) (correct answer)
- fortitas, fortitatis (f.), formed by adding the suffix -tas directly to the full nominative form fortis, following the same pattern as bonitas from bonus and veritas from verus
- fortior, fortioris, formed by adding the comparative suffix -ior to the stem, which can function nominally in Latin to express the quality in a heightened or abstract sense
- fortimen, fortiminis (n.), formed by adding the suffix -men to the adjective stem forti-, following the pattern seen in verbal derivatives like flumen from fluere and nomen from noscere
Explanation: When Latin converts adjectives into abstract nouns expressing a quality or state, specific suffixes attach to specific stem types. Recognizing which suffix pairs with which stem — and what the resulting genitive looks like — is the core skill being tested here.
The adjective fortis, forte belongs to the third declension, and its stem is forti-. Latin regularly forms abstract nouns of quality from such stems using the suffix -tudo, producing a third-declension feminine noun. So forti- + -tudo = fortitudo, fortitudinis — "bravery" or "strength." You can verify this pattern with magnitudo (greatness) from magnus, longitudo (length) from longus, and multitudo (multitude) from multus. Answer A correctly identifies both the mechanism and the outcome.
Answer B tempts you by invoking the real suffix -tas/-tatis, which does form abstract nouns — but from second-declension adjective stems, not third. Bonitas comes from bonus (second declension) and veritas from verus (second declension). Attaching -tas directly to fortis as if it were the stem is a category error; the correct form would be fortitas, which does not exist in classical Latin.
Answer C confuses a grammatical form with a word-formation process. The comparative fortior can sometimes function as a noun ("the braver one"), but this is a syntactic usage, not derivational morphology — it does not create an abstract noun meaning "bravery."
Answer D misleads by correctly identifying that -men forms nouns, but that suffix derives from verbal roots (flumen from fluere, nomen from noscere), not from adjective stems.
Your study tip: memorize suffix-to-stem pairings — -tudo for third-declension adjective stems, -tas for second-declension stems, -men for verbal stems. Suffix and source must match.
Question 2
The Latin root reg- (to rule, guide straight) appears in multiple word-family members. A student correctly identifies rex, regis (king) and regere (to rule). Which of the following adjectives is built from this same root using a standard Latin adjectival suffix, and what does that suffix contribute to the meaning?
- regens, regentis — 'ruling,' formed by adding the participial ending -ns/-ntis to the present stem reg-, functioning as the present active participle and used adjectivally to describe an ongoing action
- rectus, -a, -um — 'straight, correct,' formed by adding -tus to the root reg- with the expected consonant change, functioning as the perfect passive participle and used adjectivally to describe a completed state
- regiosus, -a, -um — 'full of ruling,' formed by adding -osus to the stem regio-, a suffix indicating abundance or fullness of the quality named by the base noun (cf. gloriosus from gloria)
- regalis, -e — 'royal, kingly,' formed by adding -alis to the noun stem reg-, a suffix that creates adjectives meaning 'of or pertaining to' the base noun (cf. mortalis from mors, navalis from navis) (correct answer)
Explanation: When Latin builds adjectives from nouns, it uses specific suffixes that signal particular relationships. The suffix -alis/-ale means "of or pertaining to" the base noun — it's one of the most productive adjectival suffixes in Latin and the direct ancestor of English -al (royal, naval, mortal). Recognizing these suffix patterns is exactly what this question tests.
The correct answer is D. Regalis, -e attaches -alis to the noun stem reg- (from rex, regis, "king"), yielding "royal" or "kingly" — precisely "of or pertaining to a king." The parallel with navalis from navis and mortalis from mors confirms the pattern: noun stem + -alis = adjective of relation.
Here's why the other options fall short. A is actually correct Latin — regens, regentis is the genuine present active participle of regere — but the question asks specifically about an adjectival suffix attached to the root, not a participial form. Participles are verbal adjectives formed differently, from the verb's present stem with -ns/-ntis. B presents a real problem: rectus does come from regere, but the consonant change (reg- → rect-) isn't just "expected" — it reflects the combination of reg- with the participial suffix -tus, producing a perfect passive participle. More importantly, the question asks which word uses a "standard adjectival suffix," and participles are verbal forms, not pure adjectives. C is a fabricated form — regiosus doesn't exist in Latin. The -osus suffix attaches to nouns (like gloria → gloriosus), not to regio in this invented construction.
Your study tip: memorize the core adjectival suffixes — -alis, -aris, -osus, -icus, -ilis — and what relationship each signals. Knowing these unlocks enormous Latin vocabulary.
Question 3
A Latin 2 student is studying the word family built on the root vid-/vis- (to see). She has learned videre (to see) and wants to extend her vocabulary by recognizing derived forms.
Which pairing correctly matches a derived Latin noun AND a derived Latin adjective from the vid-/vis- root, while accurately identifying the stem from which each is built?
- Noun: visor, -oris (m.) from participial stem vis- + -or, denoting an abstract state of seeing; Adjective: visibilis, -e from participial stem vis- + -bilis — both correctly built on the participial stem
- Noun: videntia, -ae (f.) from present stem vid- + -entia; Adjective: visibilis, -e from participial stem vis- + -bilis — the noun uses the present stem, while the adjective uses the participial stem
- Noun: visio, -onis (f.) from participial stem vis- + -io; Adjective: vidalis, -e from present stem vid- + -alis — both fully attested in classical Latin prose and poetry
- Noun: visio, -onis (f.) from participial stem vis- + -io; Adjective: visibilis, -e from participial stem vis- + -bilis — both correctly built on the participial stem and denoting 'a seeing/vision' and 'capable of being seen' respectively (correct answer)
Explanation: When building Latin vocabulary from a root like vid-/vis-, you need to track which stem each suffix attaches to. The verb videre gives you two key stems: the present stem vid- and the participial (perfect passive) stem vis-. Different suffixes prefer different stems, and recognizing these pairings is exactly what this question tests.
Option D is correct because both words are properly formed and accurately described. Visio, -onis (f.) attaches the nominalizing suffix -io to the participial stem vis-, producing the concrete noun meaning "a seeing" or "vision." Likewise, visibilis, -e attaches -bilis (meaning "capable of being ed") to that same participial stem vis-, yielding "capable of being seen." Both formations are genuinely attested in Latin, and the explanation of each stem is accurate.
Option A stumbles on the definition of visor: a visor is an agent noun (one who sees), not an abstract state. Calling it "an abstract state of seeing" is a significant semantic error that makes the pairing incorrect regardless of the stem analysis.
Option B gets the stem analysis right for both words individually, but videntia — while plausible as a formation — is not a well-attested classical Latin noun the way visio is. This makes it a weaker, potentially fabricated example compared to D.
Option C pairs visio correctly but then invents vidalis, -e, which is not an attested classical Latin adjective. The claim that both are "fully attested in classical Latin prose and poetry" is false.
Your study tip: always verify two things — the stem a suffix attaches to and whether the resulting word actually exists in Latin. Plausible-looking formations can still be unattested.
Question 4
Read the following brief Latin passage and answer the question below.
Miles fortis in pugna magna et longa laborabat. Fortitudo eius omnibus nota erat. Denique imperator eum laudavit et laudationem longam de virtute militis habuit.
In the passage above, the words fortis, fortitudo, and laudavit, laudationem represent members of two different word families. Which statement most accurately describes the morphological relationship within these pairs?
- Fortis and fortitudo are not morphologically related but are synonymous loanwords from Greek; laudavit and laudationem share the participial stem laudat-, with laudatio correctly formed by the suffix -io indicating an ongoing habitual action rather than a single completed act.
- Fortis (adjective) and fortitudo (abstract noun) share the stem fort-, with fortitudo formed by adding -tudo to the present-tense verb stem fortire; laudavit (verb) and laudationem share the stem laud-, with laudatio formed by adding -atio directly to the present infinitive stem.
- Fortis (adjective) and fortitudo (abstract noun) share the stem fort-, with fortitudo formed by adding -itudo to the adjective stem to produce an abstract noun of quality; laudavit (verb) and laudationem (action noun accusative) share the stem laudat-, with laudatio formed by adding -io to the participial stem. (correct answer)
- Fortis (adjective) and fortitudo (abstract noun) share the stem fort-, with fortitudo formed by adding -itudo to derive an abstract noun; laudavit (verb, perfect) and laudationem share the stem laud-, but laudatio is formed by adding -atio to the present stem, not the participial stem, because -atio attaches before the perfect is formed.
Explanation: When you see a question about Latin word families, your job is to trace how stems and suffixes combine to build new words — this tests your understanding of Latin morphology, not just vocabulary.
The key to this passage lies in recognizing two separate derivational processes. Fortis is a third-declension adjective with stem fort-. The suffix -itudo attaches directly to adjective stems to create abstract nouns of quality — think of magnus → magnitudo, or longus → longitudo. So fortitudo means "strength/bravery" as a quality, derived cleanly from the adjective stem. For the second pair, laudavit is the third-person singular perfect active indicative of laudo. The perfect system builds on the participial stem laudat- (from the perfect passive participle laudatus). The suffix -io then attaches to that participial stem laudat- to produce laudatio, an action noun meaning "a praising" or "speech of praise." Answer C captures both of these processes precisely and correctly.
Answer A is wrong on multiple counts — fortis and fortitudo are native Latin words with a clear morphological connection, not Greek loanwords, and -io does not signal habitual action. Answer B contains a serious error: it claims fortitudo derives from a verb fortire, which does not exist; fortitudo comes from the adjective, not a verb. It also misidentifies the laudatio stem as the present infinitive stem rather than the participial stem. Answer D invents a rule — that -atio attaches "before the perfect is formed" — which has no basis in Latin grammar; -atio always attaches to the participial stem laudat-.
Your study tip: memorize the major Latin derivational suffixes (-tudo, -tas, -io, -ura) and which stem class each one attaches to — adjective stem vs. participial stem. That distinction alone will unlock dozens of vocabulary connections.
Question 5
Latin uses the suffix -bilis to form adjectives indicating 'able to be done' (passive) or occasionally 'able to do' (active). Given the verb movere (to move; principal parts: moveo, movere, movi, motum), which analysis of a -bilis derivative is entirely correct?
- Movibilis, -e ('able to be moved') is the standard classical form, built by adding -bilis directly to the present infinitive stem move-, following the same pattern as amabilis from amare and terribilis from terrere
- Mobilis, -e ('moveable, able to be moved') is built from the participial stem mot- with a phonological adjustment before -ilis yielding mob- + -ilis, and carries a passive meaning consistent with the standard -bilis pattern for transitive verbs (correct answer)
- Motibilis, -e ('able to be moved') is the standard classical form, built from the participial stem mot- plus -ibilis, with a connecting vowel -i- inserted between the consonant-ending stem and the suffix as a regular phonological rule
- Mobilis, -e ('able to move, capable of self-motion') carries an active meaning because movere is an intransitive verb of motion, and -bilis on intransitive verbs always produces active-sense adjectives denoting capacity for independent movement
Explanation: When Latin attaches -bilis to a verb, you need to ask two questions: what stem is used, and what meaning results? The suffix typically attaches to the present stem for first- and second-conjugation verbs, but the classical form isn't always predictable — sometimes phonological history obscures the connection.
B is correct because mobilis derives from the participial/perfect stem mot- (from motum, the fourth principal part), where the sequence mot- + -bilis underwent a regular consonantal shift: the voiceless stop t became voiced (d), then further assimilated before the liquid b, producing mob- + -ilis → mobilis. The meaning "able to be moved / moveable" is passive, which is the standard -bilis pattern for transitive verbs. This is the genuine classical form you encounter in texts.
A is wrong because movibilis is not a classical Latin word. While amabilis (from amare) and terribilis (from terrere) do attach -bilis to the present stem, movere does not follow this pattern — the attested form is mobilis, not movibilis. Don't assume all verbs form -bilis adjectives identically.
C is wrong because motibilis is invented. There is no regular rule inserting -i- between a participial stem and -bilis to produce classical adjectives; this distractor fabricates a plausible-sounding but nonexistent form.
D is wrong because movere is primarily transitive (you move something), and mobilis carries the expected passive sense. The claim that -bilis on intransitive verbs always yields active meaning is an oversimplification — context and attestation matter more than that rule.
Study tip: Always check the fourth principal part when working with -bilis derivatives — the participial stem often drives the form more than the infinitive does.
Question 6
Latin word families often include a verb, an agent noun (-tor/-sor), an action noun (-tio/-sio), and a result/product noun (-tura/-sura). Given the verb colere (to cultivate, tend; principal parts: colo, colere, colui, cultum), which statement correctly distinguishes two members of this word family AND accurately describes how their meanings differ?
- Cultio, -onis (f.) — 'one who cultivates' (agent noun from participial stem cult- + -io); cultura, -ae (f.) — 'the act of cultivating' (action noun from the same stem cult- + -ura) — both suffixes interchangeable in classical Latin for these semantic roles
- Cultor, -oris (m.) — 'one who cultivates, a farmer or worshipper' (agent noun from participial stem cult- + -or); cultura, -ae (f.) — 'cultivation, culture' (result/product noun from the same stem cult- + -ura) — the former names the person, the latter the practice or product (correct answer)
- Cultor, -oris (m.) — 'the act of cultivating' (action noun from participial stem cult- + -or); cultus, -us (m.) — 'the cultivator' (agent noun formed by using the participial stem as a fourth-declension substantive) — -or on participial stems signals action rather than agency
- Cultura, -ae (f.) — 'one who cultivates' (agent noun formed by adding -ura to the present stem col- with a vowel change); cultio, -onis (f.) — 'the result of cultivation' (result noun from participial stem cult- + -io) — agent nouns in -ura are a common feature of classical Latin
Explanation: When you encounter Latin word family questions, your job is to match each suffix to its correct semantic role: -tor/-sor creates agent nouns (the person doing the action), -tio/-sio creates action nouns (the act itself), and -tura/-sura creates result or product nouns (what comes from the action). All three build off the participial stem, which you extract from the fourth principal part — here, cultum → cult-.
Answer B is correct because it accurately applies both suffixes. Cultor, -oris (m.) adds -or (the masculine form of the agent suffix) to cult-, producing "one who cultivates" — a farmer, caretaker, or worshipper. Cultura, -ae (f.) adds -ura to cult-, producing "cultivation" or "culture" — the practice and its product. The distinction B draws is precise: one names the person, the other names the practice or product. This is exactly the semantic split the question is testing.
Answer A reverses the meanings entirely, calling cultio an agent noun and cultura an action noun — both wrong. It also falsely claims the suffixes are interchangeable in classical Latin; they are not, and each carries a distinct semantic function. Answer C misidentifies -or as signaling action rather than agency, which is backwards, and incorrectly describes cultus, -us as an agent noun — cultus actually means "cultivation, care, or worship" as a fourth-declension abstract noun. Answer D fabricates a category ("agent nouns in -ura") that does not exist in Latin; -ura never forms agent nouns.
Your study tip: memorize the suffix-to-role pairing (-tor = person, -tio = act, -tura = result) as a fixed trio — questions will often swap these roles to create tempting distractors.
Question 7
A student learning Latin word families reads that navis, navis (f.) means 'ship.' She wants to predict the adjective meaning 'of or pertaining to ships / naval' and the abstract noun meaning 'seamanship / navigation.' Applying standard Latin derivational patterns, which prediction is correct?
- Adjective: navalis, -e, formed by adding -alis to the noun stem nav-; Abstract noun: navigatio, -onis (f.), formed not directly from navis but from the compound verb navigare via its participial stem navigat- plus -io (correct answer)
- Adjective: navalis, -e, formed by adding -alis to the noun stem nav-; Abstract noun: navitas, -tatis (f.), formed by adding -itas directly to the noun stem nav-, following the same derivational pattern as civitas from civis
- Adjective: navidus, -a, -um, formed by adding -idus to the noun stem nav- to mean 'full of ships' or 'ship-like'; Abstract noun: navigatio, -onis (f.), formed from the compound verb navigare via its participial stem navigat- plus -io
- Adjective: navosus, -a, -um, formed by adding -osus to the noun stem nav- to mean 'pertaining to ships'; Abstract noun: navitas, -tatis (f.), formed by adding -itas to the noun stem nav-, a standard pattern for third-declension i-stem nouns
Explanation: When predicting Latin derivatives, you need to know two things: which suffix attaches to which base, and whether a word is formed directly from a noun or indirectly through a verb. These two criteria together will sort this question quickly.
The adjective meaning "of or pertaining to ships" follows the -alis/-ale pattern, which attaches to a noun stem to create relational adjectives. The stem of navis is nav-, so nav- + -alis → navalis, -e. This is exactly the pattern that gives you regalis from rex/reg-, mortalis from mors/mort-, and so on. So far, options A and B agree. The difference lies in the abstract noun. "Navigation/seamanship" is not a simple quality of a noun — it describes a process or act, which in Latin is typically expressed by -io, -ionis attached to a participial stem. The verb navigare ("to sail," itself a compound of navis + agere) produces the perfect passive participle stem navigat-, giving navigat- + -io → navigatio, -onis. This makes A correct.
B is wrong because -itas forms abstract nouns from adjectives (e.g., libertas, civitas from civis works because civis is functioning adjectivally in context) — it does not attach productively to bare noun stems to create process nouns. Navitas is not a classical Latin word.
C is wrong because -idus signals a state or tendency (e.g., timidus, avidus) — it does not mean "pertaining to" and would not yield a naval adjective.
D is wrong on both counts: -osus means "full of/characterized by" (like gloriosus), not "pertaining to," and navitas has the same problem as in B.
Your study tip: memorize suffix functions — -alis = "relating to," -osus = "full of," -idus = "inclined toward," and -io = "act/process (from a verbal stem)." Confusing these suffix meanings is the most common trap in Latin word-family questions.
Question 8
The Latin suffix -tor/-sor regularly forms agent nouns (nouns meaning 'one who does X') from verb roots. A student encounters laudare (to praise) and must decide which derived noun correctly follows this pattern — and must also recognize a subtle difference in what the competing suffix -tio/-sio would produce instead.
- laudor, -oris (m.) — 'the quality of being praised,' built from the present stem laud- plus -or following the same pattern as amor from amare; contrast laudatio, -onis (f.), which in this analysis denotes the agent performing the act of praise
- laudator, -oris (m.) — 'one who praises,' built from the present stem laud- plus the single suffix -ator; contrast lauditio, -onis (f.), built from the present stem laud- plus -itio to mean 'the habit of praising' — agent noun vs. habitual action noun
- laudator, -oris (m.) — 'one who praises, a praiser,' built from the participial stem laudat- plus -or; contrast laudatio, -onis (f.), built from the same participial stem plus -io to mean 'an act of praising, a eulogy' — agent noun vs. action noun (correct answer)
- laudatrix, -icis (f.) — 'a praiser,' built from the participial stem laudat- plus -rix, the primary agent-noun suffix in classical Latin for all genders; contrast laudatio, -onis (f.), built from laud- plus -atio to mean 'a particular type or style of praise'
Explanation: When Latin verbs generate nouns, the key is identifying the right stem before attaching a suffix. For first-conjugation verbs like laudare, the participial stem is formed by taking the perfect passive participle (laudatus) and stripping -us, leaving laudat-. Two major suffixes then attach to this stem: -or to create an agent noun (someone who performs the action), and -io to create an action/abstract noun (the act or product of the action itself).
Answer C is correct because laudator is built precisely this way: laudat- + -or = laudator, -oris (m.), meaning "one who praises." Similarly, laudatio = laudat- + -io, giving you an action noun meaning "an act of praising" or "a eulogy" — a real and common Latin word you'll encounter in Cicero and other authors.
Answer A fails on two counts: laudor is actually the present passive indicative form of laudare ("I am being praised"), not a noun at all, and the claim that laudatio denotes the agent is backwards — -tio/-sio forms action nouns, never agent nouns.
Answer B gets laudator right but invents lauditio, which is not a Latin formation. The correct action noun inserts no extra vowel between the participial stem and -io; the stem already ends in -at-, so the form is laudatio, not lauditio.
Answer D is a trap: -trix does exist (e.g., victrix), but it is the feminine agent-noun suffix, not the primary form for all genders. -tor is the standard masculine/general form.
Study tip: Always locate the participial stem first — agent nouns (-tor) and action nouns (-tio) both build from it, so mastering that one stem unlocks both derivations.
Question 9
A Roman student encounters the verb amare (to love) and is asked to identify which of the following Latin words belongs to the same word family and functions as an abstract noun derived directly from the verb stem.
Which Latin word is the abstract noun most directly derived from the root of amare, and what does it primarily denote?
- amor, amoris (m.) — the state or feeling of love, derived from the root am- with the nominal suffix -or indicating an abstract quality or condition, attaching directly to the root without an intermediate participial stem (correct answer)
- amicus, -i (m.) — a friend, derived from the root am- with the adjectival suffix -icus later substantivized to denote a person characterized by that quality, and therefore naming a person rather than an abstract state
- amabilis, -e — worthy of love or capable of being loved, derived from the root am- with the suffix -bilis indicating possibility or passive capacity, and functioning grammatically as an adjective rather than an abstract noun
- amatio, -onis (f.) — the act of loving, derived from the participial stem amat- with the suffix -tio denoting a process or verbal action, and therefore naming an action rather than an enduring abstract state
Explanation: When Latin verbs spawn related nouns and adjectives, the key question is: what kind of word is being formed, and how directly does it connect to the root? Abstract nouns name states, qualities, or conditions — not people, actions, or capacities. Keep that distinction in mind as you work through this family.
The root of amare is am-, and A correctly identifies amor, amoris as the abstract noun built directly from that root. The suffix -or (as in timor from timēre, or dolor from dolēre) attaches to a verbal root to create a masculine third-declension noun naming an enduring state or condition — not a fleeting action, not a person, not a capability. Amor means love as a feeling or state, which is precisely what an abstract noun should capture.
B is wrong because amicus is a substantivized adjective denoting a person defined by affection. It names who someone is, not what the feeling itself is — a concrete (or at least personal) noun, not an abstract state.
C is wrong because amabilis uses the -bilis suffix to form an adjective meaning "capable of being loved." Grammatically it modifies nouns; it does not stand alone as a noun denoting the condition of love.
D is wrong because amatio uses the suffix -tio, which attaches to the participial stem (amat-) to name a verbal action or process — the act of loving as an event. That's a verbal noun, not an enduring abstract state, and the derivation runs through an intermediate stem.
A quick tip: when identifying abstract nouns, check both the suffix and the meaning — the word should name a state, not a person, action, or quality-of-capacity.
Question 10
Consider the Latin verb scribere (to write) and its principal parts: scribo, scribere, scripsi, scriptum.
A student wants to identify all three members of the word family — verb, noun, and adjective — built from the root of scribere. Which set correctly identifies one member of each word-class and accurately describes the suffix used to build each form?
- Verb: scribere; Noun: scriptura, -ae (f.), built from the participial stem script- plus -ura denoting result or product of the action; Adjective: scriptus, -a, -um, the perfect passive participle built from the same participial stem and functioning adjectivally to mean 'written' (correct answer)
- Verb: scribere; Noun: scriptor, -oris (m.), built from the present stem scrib- plus -or denoting an abstract state of writing; Adjective: scribilis, -e, built from the present stem plus -bilis meaning 'able to be written'
- Verb: scribere; Noun: scriptio, -onis (f.), built from the present stem scrib- plus -tio denoting the act of writing; Adjective: scripturalis, -e, built from scriptura plus -alis and commonly attested in classical prose
- Verb: scribere; Noun: scriptura, -ae (f.), built from the present stem scrib- plus -ura attached directly without a participial base; Adjective: scribax, scribacis, built from the present stem plus -ax indicating a tendency or inclination toward writing
Explanation: When analyzing Latin word families, you need to track two things simultaneously: which stem a derived form is built on, and whether the suffix description accurately reflects its meaning and function. A single error in either area disqualifies the whole answer.
Answer A gets both dimensions right. Scriptura is formed from the participial stem script- (drawn from the fourth principal part scriptum) plus the suffix -ura, which genuinely denotes the result or product of an action — hence "writing" as a physical product. Scriptus, -a, -um is the perfect passive participle, directly identical to that fourth principal part, and it functions adjectivally to mean "written." Every claim in A checks out.
Answer B fails on the noun. Scriptor is indeed a real Latin word, but it is not built with -or meaning an "abstract state" — -or here is the agent suffix, meaning "one who writes." Mislabeling the suffix's meaning is the trap; the word exists, but the description is wrong.
Answer C misidentifies the stem. Scriptio is built from the participial stem script- plus -io, not from the present stem scrib- directly. The adjective scripturalis is also largely post-classical and ecclesiastical, not standard classical prose — making the description doubly unreliable.
Answer D invents a problem with scriptura (it is not formed by attaching -ura directly to the present stem) and then offers scribax, which is not a standard attested classical Latin adjective.
Your study tip: always cross-check both the stem identity and the suffix gloss — Latin word-formation questions routinely put a real word alongside a false etymology to test exactly this double vigilance.