We are asked to find an additional premise that would make the argument more reasonable. This implies that you must first locate the evidence and conclusion, then identify a central assumption, and finally find an answer choice that supports this assumption.
The argument here is a simple one: Since students at the Willard Detention Center make their own decisions about free time, they should also make their own decisions about elective courses. The argument assumes that, for these students, decisions about what to do with free time are similar to decisions about what electives to take in school. Since we are looking for a premise to complete the argument, look for a choice that provides evidence that these things are similar. Choice (E) provides the evidence we need. If it is true that elective courses are more akin to free time than to required activities, then the conclusion that students should be able to choose their own electives is more reasonable.
