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

Only the right answer will add support for the conclusion.

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

this complexity probably masks any difference in taste due to the lack of fat.

[SUPPORT]. [SUPPORT]. [SUPPORT]. Hence, [CONCLUSION].

You caught that the conclusion makes a comparison between vanilla and chocolate, right? The author clearly implies that chocolate is more complex than vanilla, which is funny since they only gave info about the complexity of chocolate. So you should expect the right answer to have info that completes the comparison.

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

(A) Most people prefer full-fat chocolate ice cream to full-fat vanilla…

This comes close to making the same comparison as the passage, but it keys in on “full-fat” for no reason. The conclusion is actually trying to explain why people like “low-fat” chocolate just as much, when they don’t like “low-fat” vanilla as much. Tricky, but this answer is changing the subject.

(B) The subjects of previous tests were not informed…

This is bringing in something new, and it has nothing to do with whether “complexity” explains the taste test results. I hope you agree, since you’d have to add in your own reasoning to connect this to the conclusion. That’s not allowed.

(C) …the better people like it.

“The more distinct compounds” maps to the author’s description of “complexity”, so I’m cool with that part. But we’re not trying to explain an overall preference, we want to support why “low-fat” chocolate performs better in taste tests than “low-fat” vanilla.

(D) Vanilla is known to be a significantly less complex flavor than chocolate.

I couldn’t have written it better myself. This maps to the comparison the passage makes, and it fills in the missing info about the complexity. Now the conclusion makes pretty good sense.

(E) Most people are aware of the chemical complexities…

If you thought about picking this, you’re likely overthinking things. Don’t add in your own assumptions! What “people are aware of” never gets mentioned, so you can’t assume how that connects to the conclusion. Stick to carefully checking the wording itself, and you’ll live a long and happy lawyer life.

(D) is the correct answer.