1. Art museums do not usually think of their collections as capital or consider the interest income that would be generated if a portion of the capital would have been invested in another form.

(A) be generated if a portion of the capital would have been

(B) have been generated if a portion of the capital would have been

(C) be generated if a portion of the capital were

(D) be generated if a portion of the capital was（C）

(E) be generated if a portion of the capital had been

本题考虚拟语气,但我查了张道真的语法, 因为a portion of the capital为单数,所以后面也可跟was是否在商业英语中该用法不可以呢,否则D为什么错?

was好像补符合虚拟得用法吧。