Beginning last year, the B & M Foundation has funded a $400-million

Hello, Pranithare. I understand your confusion, and I was on the fence between the same answer choices before I opted for (A). Why? Because there is a subtle difference between saying that teacher effectiveness depends mostly on something, as in (A), and simply saying that it depends on something, without the qualifier, as in (D). That is, (A) tells us that school organization is the primary factor in determining teacher effectiveness, and that exists independently of the initiative; (D) presents a contributing factor, and while such a consideration may also fall outside the initiative, the situation is described as healthy, so we have no reason to doubt the initiative. Choice (A) is the safer answer to get behind, the one that is harder to argue against.

Although I have my doubts that this question would appear as is on the GMAT™, if you narrowed the options down to (A) and (D), you are definitely following a correct line of reasoning, and that can help you as you dive deeper into your preparation.

I hope that helps. Good luck with your studies.

- Andrew

I was not sold on A and I picked C because I was not getting the sense that "effective" means the same as "quality". It could be true but based on the context of the passage, I was not confident enough to say yes, they are the same.