The following sentences test correctness and effectiveness of expression. Part of each sentence or the entire sentence is underlined; beneath each sentence are five ways of phrasing the underlined material. Choice A repeats the original phrasing; the other four choices are different. If you think the ckigin. al phrasing produces a better sentence than any of the alternatives, select choice A; if not, select one of the other choices. In making your selection, follow the requirements of standard written English; that is, pay attention to grammar, choice of words, sentence construction, and punctuation. Your selection should result in the most effective sentence clear and precise, without awkwardness or ambiguity.
Some beaches are frequently contaminated by untreated sewage that flows into the ocean, which can last for several days.
A. Ocean which can last for several days.
B. Ocean that can last for several days.
C. Ocean, while contamination can last several days.
D. Ocean the contamination can last several days.