dirty water __by the chemical works __the river polluted.

B

poured by the chemical works 是表被动的过去分词短语做后置定语修饰主语
made 是谓语动词, A 中的to make 是不定式, 不能作为与
make sth polluted 使.收到污染


如不明白请追问,要是满意请【采纳】
祝学习进步

B，made by chemical works意思是被泼的。
dirty water made the river polluted.
污水使河流污染了， make something done.

过去式made. 要不现在时makes.
所以选B