单选题 The ______ of sediment in the river caused concern among environmentalists and industrialists alike; the water levels in the river were being reduced almost daily.

(A) accretion
(B) disposal
(C) catalyst
(D) alienation
(E) ethnology

【正确答案】 A

【答案解析】Accretion means "the gradual buildup" of something, and is often used in reference to geologic phenomena. If water levels were being reduced because of the buildup of sediment, then both environmentalists and industrialists might have cause for concern. The other words do not fit the context of the sentence.