Critical Reasoning

If participation in the honors creative writing class were limited to graduate students and those undergraduate students who had received at least a B+ in composition,most of the undergraduate students would be forced to take the regular creative writing class.Such a reduction in undergraduate enrollment would reduce the percentage of failing grades in the honors class.

Which of the following , if true ,would most strengthen the conclusion drawn in the second sentence above?

(A)Graduate students all scored at least B+ in composition
(B)The honors creative writing course is experiencing overcrowding due to increases in graduate enrollment.
(C)Many undergraduates would work harder to score B+ in composition rather than be excluded from honors creative writing
(D)The number of failing grades in honors creative writing has decreased in recent years.
(E)Undergraduates who scored lower than B+ in composition are responsible for a disproportionate percentage of failing grades in honors creative writing

OA is E
It requires a reflexive thinking to decipher the answer here. Can an Expert please?