请教一og语法

72.   The number of undergraduate degrees in engineering awarded by colleges and universities in the United States
                increased by more than twice from 1978 to 1985.

(A) increased by more than twice

(B) increased more than two times

(C) more than doubled

(D) was more than doubled（C）

(E) had more than doubled

答案C和D在语法上来讲都是可以的, 也是简洁的, 只不过意思上有些差别罢了. 请NN指点...

number一般都是直接加double，不用被动吧。