Answer choice (E) is actually incorrect because it is too specific.
(E) states that "Zachary's principle is based on an understanding of moral obligation that is too narrow to encompass the kinds of moral obligation artists feel toward works of art."
(E) is focused specifically on Zachary's principle being too narrow to account for art-related situations. However, this is so specific that it misses the main intention of Cynthia's response, which is to show that Zachary's principle is unsustainable and can be contradictory.
Imagine that, instead of an artist and antipornography demonstrator, Cynthia gave the example of a writer who feels morally obligated to encourage all literary works to be read in school and a teacher morally committed to preventing works deemed "inappropriate" from being read in the classroom. This uses the same logic as Cynthia's original example (which is important to note because the question is asking about the structure), but it has nothing to do with how obligated artists feel towards art. Therefore, (E) is irrelevant and incorrect. However, (C) "Zachary's principle is untenable on its own terms" still makes sense because, like Cynthia's example in the passage, this hypothetical example shows possible contradictions inherent in Zachary's claims.
Basically, Cynthia presented an example in order to support a bigger point, and (E) focused specifically on the subject matter of that example instead of addressing the underlying point, which is why it is incorrect.
Does that make sense? Please let us know if you have any additional questions!
