一道prep题，p2-sc 15，谢谢大家

p2-sc      15.   (25243-!-item-!-188;#058&002297)

In the mid-1920s the Hawthorne Works of the Western Electric Company was the scene of an intensive series of experiments that would investigate changes in working conditions as to their effects on workers' performance.

(A) that would investigate changes in working conditions as to their effects on workers' performance

(B) investigating the effects that changes in working conditions would have on workers' performance

(C) for investigating what the effects on workers' performance are that changes in working conditions would cause

(D) that investigated changes in working conditions' effects on workers' performance

(E) to investigate what the effects changes in working conditions would have on workers' performance

正确答案是b，不理解，都解释下行吗。。。谢谢

能解释下其他为什么错不？