请问OG72题

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.fficeffice" />

(A)     increased by more than twice

(B)         increased more than two times

(C)     more than doubled

(D)     was more than doubled

(E)         had more than doubled

Choice A is faulty because an adverb such as twice cannot function as an object of the preposition by. B distorts the sentence's meaning, stating that the number of engineering degrees conferred increased on more than two distinct occasions. D's passive verb was ... doubled suggests without warrant that some unnamed agent increased the number of engineering degrees. The past perfect tense in E, had... doubled, is inappropriate unless the increase in engineering degrees is specifically being viewed as having occurred further back in the past than some subsequent event. Choice C is best.

我看了好久的解释，总是无法理解B、D、E的说明，牛人或大侠们能为我详细说明一下这三个选项吗？非常感谢！