PT 1 Passage 4, Q24 Question- Clarification / Explanation Forum

[Arshavin24]

Hey everyone. I just wanted to see if any of you could give me a detailed explanation for why C is the correct answer rather than D.

I've narrowed it down to the word "suggestions" in answer choice d being the reason. I feel that if the author has used the word "reasons" in place of "suggestions", answer choice D would be the correct answer choice (and I highly doubt C would be an offered answer choice if that was the case). I would really appreciate if someone could clarify this, the Kaplan explanations 7 the Manahttan explanation for this question aren't helping. Thanks!