How will the right answer fit in terms of support and conclusion?

Only the right answer will accurately describe a flaw in the argument, but it will also be the only one that accurately describes the support and conclusion.

Highlight the main conclusion in the passage, if there is one:

his art is great.

Art student: [SUPPORT]. Thus, since [SUPPORT], [CONCLUSION].

This conclusion uses a necessary condition, but a lot of people don’t recognize that right away since there’s no strong language. Even without “must be” or a similar phrase, you need to recognize the conclusion is a matter-of-fact statement with no exceptions. That means the flaw is very likely to be mixing up sufficient and necessary conditions, even if you couldn’t spot that flaw.

That’s the flaw here for sure. The support in the first sentence doesn’t say “passionate responses” only come from “great works of art”. Just because his art “elicits intensely emotional responses” doesn’t mean it’s “great”. In other words, that support says “great” art is sufficient to “evoke passionate responses”, but not that it’s necessary.

Map the wording of the answers to the wording of the passage:

(A) One of the premises…assume the truth of that conclusion.

You know you’re looking for a sufficient/necessary answer, so this doesn’t map anyway. But where does the author seem to be assuming that Reilly’s art is great? Nowhere.

(B) …treats a condition that is necessary…as if it must also be sufficient…

This is the only answer that gets into necessary conditions, so people who just want the best score will pick this and keep going without thinking about it.

Buuut, of course it all maps. The “condition that is necessary” is the “passionate responses”. The first sentence basically says, if art is great, it must “evoke passionate responses”. The conclusion says since Reilly’s art “elicits intensely emotional responses”, that’s enough to conclude his art is great. That’s exactly what taking a necessary condition to be sufficient looks like.

(C) …to an atypical instance of that class.

I could see you thinking this answer is okay at first, but everybody’s spidey sense should be tingling when they see “atypical”. How would we know whether Reilly or his art are typical or not? There’s nothing about that in the passage.

(D) …a generalization derived from an insufficient number of instances…

Ooh, that’s quite backwards. The generalization in the argument is at the beginning, and the “instance” about Reilly is derived from that, not the other way around.

(E) …from premises that do not involve statements about values.

Clearly the the premises and conclusion both involve the same “value judgment”, that is “great works of art”.

(B) is the correct answer.

Common pattern/s in this question: It may be easier to recognize that authors are mixing up sufficient and necessary conditions when the support sounds like, “If…, then…” But clock the conclusion using a necessary condition anytime it leaves no wiggle room and makes no exceptions, without changing the subject.