GMATPre(2）15题请教

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

同問 有沒有NN可以解釋一下為什麼選(B)?

A：their指代不清晰；changes as to明显不正确；
C：for表目的不正确；performance are that....逻辑不正确；
D：conditions‘s effect不对；
E：changes和would两个谓语动词