Establish/Maintain a Formal Argument Style Practice Test

Read this mixed-style letter to a newspaper editor about keeping the library open later: “Extended hours would be beneficial for students who need a quiet place to study. Furthermore, it would enhance access to books. But honestly, it’s super annoying when the doors close early.” Which sentence breaks the formal style?

In this informal email to a friend about school lunch, a student writes: “I want better options because the food is good sometimes, but not always.” Which revision makes the sentence more formal for a letter to the principal?