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

(A) generated through wind power now than it was in 1990.

(B)generated through wind power now as it was in 1990.

(C)generated through wind power now as was the case in 1990.

(D)now generated through wind power as it was in 1990.

(E)now generated through wind power as was the case in 1990.

为什么是选Ｃ啊？不懂耶！！请赐教．