OG11-4 for 的用法 菜鸟举手，希望NN指教

A survey by the National Council of Churches showed that in 1986 there were 20,736 female ministers, almost 9 percent of the nation's clergy, twice as much as 1977.

a) twice as much as 1977

b) twice as many as 1977

c) double what it was in 1977

d) doulbe the figure for 1977

e) a number double that of 1977's

其余选项都可以理解，这里只是想问一问 D选项当中 for的用法，追了几个以前的贴子，没有人提及这个用法，希望大NN们不吝赐教，谢谢

完全没人理我吗………………

还是题目太简单了，如果是题目太简单了，请大家不吝赐教啊～～～～

我也很想知道这个问题，有人能帮忙解答一下吗？先谢过了！

我在Merriam-Webster's Online Dictionary, 11th Edition中查到for的用法“used as a function word to indicate duration of time or extent of space ”但这里接的应该是一个时间段而不是时点啊？

盼望有人能解答。

twice as many as in 1977

是不是更合适，期待...