If Charles had spent half as much time attending his classes as he did complaining about them, he would have been a good student.

(A) had spent half as much time attending his classes as he did complaining
(B) had spent half as much time to attend his classes as he did to complain
(C) were to spend as much time attending his classes as he does complaining
(D) were to spend half as much time attending his classes as complaining
(E) should spend half as much time attending his classes as to complain


OA A

Source: GMAT Prep