We're looking here for the answer choice that does NOT help explain the issue in the stimulus. The issue is: a greater percentage of people recover when they're treated in small, rural hospitals than in large, urban ones.
So to recap: 4 answer choices will help explain why this is true. These are NOT the answer. One answer choice will not help explain why this is true. This IS the answer.
(C) tells us that the large hospitals get doctors from elite schools but that this has no correlation to how quickly people recover. But we're not concerned with the rate of recovery. We're concerned with how many of them do, compared to the proportion who do at small hospitals. (C) leaves all of this in question.
(A) gives us a reason smaller hospitals are better.
(B) gives us a reason why larger hospitals are worse.
(D) is like (B).
(E) is like (D) and (B)--tells us why large hospitals are worse.
I hope this helps!
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