大全987答案错误？

cdpku2002

刚开始做，不过怎么第二道题的答案就错了啊。
2.    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
(E) reduces the amount of phosphates allowed for dumping by municipalities

大全说是A，OG明明是D。有没有一个可信的答案列表？

看到前面老帖子大家争论说A对，可是OG的勘误从来没更正过答案，如果出了这倒题我不信大家不选og的答案。。。

千妮迪公主

我也发现了，正想问呢，到底咋回事啊？

学海无涯啊

I think the ans should be "D". Here's the explanation:

The Act is an ongoing, living document - it doesn't apply retroactively, it's always in effect.

If we were to use the verb "had been allowed", then we'd only be speaking about what they were allowed to do in the past. By using "are allowed", we recognize that the Act continues to govern what people are allowed to do today.