【正确答案】 B

【答案解析】[注释] 词汇释义题。本题问：根据上下文，第1段中“effluents”在含义上最接近下面哪一个词?参阅第1段倒数第2句：An insistence on treatment of the various effluents would have necessitated expenditures on treatment equipment that in turn would have given rise to higher operating costs．本句中effluents前有 treatment，后有necessitated expenditures on treatment equipment。可见， effluents是从工厂里流出后要被处理的东西，即为drainage(排出的污水)。
注意：解这类题的技巧是注意并划出前后的隐含信息词，然后加以归纳和推理。