大全-7-14 求教

Which of the following best completes the passage below?

At a recent conference on environmental threats to the North Sea, most participating countries favored uniform controls on the quality of effluents, whether or not specific environmental damage could be attributed to a particular source of effluent. What must, of course, be shown, in order to avoid excessively restrictive controls, is that______

(A) any uniform controls that are adopted are likely to be implemented without delay

(B) any substance to be made subject to controls can actually cause environmental damage

(C) the countries favoring uniform controls are those generating the largest quantities of effluents

(D) all of any given pollutant that is to be controlled actually reaches the North Sea at present（B）

(E) environmental damage already inflicted on the North Sea is reversible

为啥是B？？

为了避免过分的限制,必须要把一些不会对环境造成破坏的subtance从control list去除.所以我们必须要搞清楚被control的substance是否真会对环境造成影响了.好像做过这道题目捏

At a recent conference on environmental threats to the North Sea, most participating countries favored uniform controls on the quality of effluents, whether or not specific environmental damage could be attributed to a particular source of effluent.

是不是这个意思：不论ED是由某个污染源造成的，只要可能的污染源，统统控制？

如果是，那么就好理解了。。。

谢谢！