1.        Never before had taxpayers confronted so many changes at once as they had in the Tax Reform Act of 1986.

(A) so many changes at once as they had in

(B) at once as many changes as

(C) at once as many changes that there were with

(D) as many changes at once as they confronted in（D）

(E) so many changes at once that confronted them in

I chose A, because I thought "never before had ..." should follow with "so many"

Also, what's wrong with A? Pls help.