大全2,时态??

A 1972 agreement between Canada and the United States reduced the amount of phosphates that municipalities had been allowed to dump into the Great Lakes.

(A) reduced the amount of phosphates that municipalities had been allowed to dump

(B) reduced the phosphate amount that municipalities had been dumping

(C) reduces the phosphate amount municipalities have been allowed to dump

(D) reduced the amount of phosphates that municipalities are allowed to dump     （D）

(E) reduces the amount of phosphates allowed for dumping by municipalities

大全上的答案是A,但是OG11的答案是D,请牛人指点一下