请教OG-62

62。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

.......

答案是B。我有点不懂这道题目，请DX指点。

thanks. understand now.