“Affluent” means very wealthy. It is the opposite of “impoverished,” which means very poor. “Despicable” means evil and wicked; “comely” means very cute and beautiful; and “winsome” means charming and appealing.

When someone is “prosperous,” that person is said to “do well” for himself or himself. That is, he or she is accomplishing the tasks and goals that he or she has set. Often, such prosperity is indicated by an increase in material wealth. This is the sense in which the word is most often used, as in, “The banker was the most prosperous man in town, owning fifteen cars and two large houses.” In a more general sense, it can mean “flourishing,” which is related to “flowering,” here meaning “coming to full development” (like a plant coming to flower).

Do not confuse this word with the word “duel,” which means “a fight between two people.” The words are related but not the same. “Dual” merely means “being two in number.” For instance, one can say that someone seems to have “dual personalities,” when they are (for instance) happy at one moment and then nasty and slanderous at another. The word “binary” means “two” and is related to the word “combination,” which means “the bringing together of two things.”

You might be tempted to see the word “arbiter” in “arbitrary.” They are not unrelated, for both pertain to a judgment being made. However, when something is "arbitrary," it is done at the whim of the one judging. It has no real reason other than that person’s desires or passions. Therefore, an “arbitrary” decision could be called “whimsical.” All of the other answers (except “flimsy”) are meant to trick you.

The word "affluent" does have roots that mean to flow. While this meaning was once upon a time reflected in the word, it no longer is used in this manner. Instead, the word means wealthy—as though someone is "flowing" with money. Thus, the only option that is appropriate is "prosperous." (Note that "mobile" is not the same as flowing. A walking person is mobile—yet is not flowing, strictly speaking.)

The adjective "adamant" is etymologically related to the word "diamond"—the hardest stone. Someone who is "adamant" is "hard" in the sense of being relentless, unyielding, or insistent.

When someone is affluent, one could figuratively say that such a person “flows with wealth.” The word “affluent” originally was derived form the Latin for “to flow,” which is clearly detectable in the “-fluent” portion of the word. While such a person might be cultured, overachieving, or even snobby, the best description of “affluence” is the state of having wealth.

Something that is "drastic" is extreme and often surprising. A drastic reduction in work output means that the amount of work being done has reduced significantly. The word "radical" comes from Latin roots meaning, to the root. A radical change is one that alters something significantly. This is the best option among those provided. Do not be tricked into "thrilling." A drastic event might be exciting or thrilling; however, this is not the direct meaning of "drastic."

Something that is "opulent" is very expensive, to the point of being showy. Thus, the word "lavish" is the only option that matches this meaning. Note, however, that "opulent" can be used as an adjective that means wealthy more generally as well.

The word "culpable" comes from the Latin "culpa," meaning guilt. A culpable person is a guilty person. Thus, the best answer is "responsible." This is meant in the sense of saying that someone is guilty, as when we say, "He was responsible for the crime." Now, "condemned" and "imprisoned" may be tempting, but culpability is first and foremost about guilt. Whether or not it causes condemnation or imprisonment is secondary. Culpability is a matter of inherent responsibility, not the results of the action for which the person is responsible.