请教一道GMATPrep模考中遇到的as much ...as题

There are hopeful signs that we are shifting away from our heavy reliance on fossil fuels: more than ten times as much energy is generated through wind power now than it was in 1990

A) generated through wind power now than it was

B) generated through wind power now as it was

C) generated through wind power now as was the case

D) now generated through wind power as it was

E) now generated through wind power than was the case

答案是c

我选的是b

对于as much ...as实在是晕，看了置顶的帖还是迷迷糊糊，还请nn们分析一下：）

B) generated through wind power now as it was

It is not clear what "it" refers to. The reason is simple, the energy generated now is not the same energy generated before.  Hence B is wrong.

Can anyone remember the question about the earthquake in the eastern coast comparing with another one of comparable scale happening in the western coast? The "it" was wrongly used also. 

C should be correct:

谢谢：）讲得很清楚，明白了。原来是it指代的问题

另外，在置顶找到了一个相关的好帖，有兴趣的可以继续看：）

http://forum.chasedream.com/dispbbs.asp?BoardID=23&ID=43901