lsat 2001年6月 21

21、Professor Chan: The literature department’s undergraduate courses should cover only true literary works, and not such frivolous material as advertisements.

Professor Wigmore: Advertisements might or might not be true literary works but they do have a powerfully detrimental effect on society—largely because people cannot discern their real messages. The literature department’s courses give students the critical skills to analyze and understand texts. Therefore, it is the literature department’s responsibility to include the study of advertisements in its undergraduate courses.

Which one of the following is an assumption on which Professor Wigmore’s argument depends?

(A) Texts that are true literary works never have a detrimental effect on society.

(B) Courses offered by the literature department cannot include both true literary works and material such as advertisement.

(C) Students who take courses in the literature department do not get from those courses other skills besides those needed to analyze and understand texts.

(D) Forms of advertising that convey their message entirely through visual images do not have a detrimental effect on society.（B）

(E) The literature department’s responsibility is not limited to teaching students how to analyze true literary works.

这道题是什么样的逻辑思路？请教