170. A large rise in the number of housing starts in the coming year should boost new construction dollars by several billion dollars, making the construction industry’s economic health much more robust than five years ago.

(A) making the construction industry’s economic health much more robust than five years ago

(B) and make the construction industry’s economic health much more robust than five years ago

(C) making the construction industry’s economic health much more robust than it was five years ago

(D) to make the construction industry’s economic health much more robust than five years ago（C）

(E) in making the construction industry’s economic health much more robust than it as five years ago

答案给出了c个人觉得应该是a呀,更简洁it was 可以省去...有点不明白而且it在这里指代是不是也值得商榷

对a质疑的理由,如果补足主谓语是不是可以认为是和making动作的发出者进行比较

如果这个质疑不成立的话,a是不是更合适,而且简洁呢?