请问一道语法题的结构

xiuyiwei1

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

不是很懂这成分关系，网上说twice跳跃修饰20 percent of young adults，同位语？

xiuyiwei1

没人能回答一下吗？

benjaminsandro

主语补语