doubling用法讨论

According to surveys by the National Institute on Drug Abuse, about 20 percent of young adults used cocaine in 1979, doubling those reported in the 1977 survey.
(A) doubling those reported in the 1977 survey
(B) to double the number the 1977 survey reported
(C) twice those the 1977 survey reported
(D) twice as much as those reported in the 1977 survey
(E) twice the number reported in the 1977 survey

OA：E。其中twice跳跃used cocaine修饰20 percent of young adults.     这题选E  选A 问题出在哪里呢？

The number of people flying first class on domestic flights rose sharply in 1990, doubling the increase of the previous year.  

A. doubling the increase of

B. doubling that of the increase in

C. double as much as the increase of

D. twice as many as the increase in    (A)

E. twice as many as the increase of