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 _____.

• Aany uniform controls that are adopted are likely to be implemented without delay  
• Bany substance to be made subject to controls can actually cause environmental damage  
• Cthe countries favoring uniform controls are those generating the largest quantities of effluents  
• Dall of any given pollutant that is to be controlled actually reaches the North Sea at present  
• Eenvironmental damage already inflicted on the North Sea is reversible