讨论一个题目official guide_SC的第48题

freegale

题目和解答如下：

48. The golden crab of the Gulf of Mexico has not been fished commercially in great numbers, primarily on account of living at great depths-- 2,500 to 3,000 feet down.
(A)        on account of living
(B)        on account of their living
(C)        because it lives
(D)        because of living
(E)        being they live
As used in choices A, B, and D, the phrases on account of and because of are unidiomatic; because, which appears in C and E, is preferable here since because can introduce a complete subordinate clause explaining the reason why the golden crab has not been fished extensively. B and E also produce agree¬ment errors by using the plural pronouns their and they to refer to the singular noun crab. Choice D, like A, fails to provide a noun or pronoun to perform the action of living, but even with its the phrases would be more awkward and less clear than it lives. C, which uses because and it as the singular subject of a clause, is the best choice.

我觉得，C固然是对的，但是“the phrases on account of and because of are unidiomatic”好像这个说法不对吧？
如果改成：The golden crab of the Gulf of Mexico has not been fished commercially in great numbers because of/on account of living……
或者：The golden crab of the Gulf of Mexico has not been fished commercially in great numbers, primarily because of its living……是不是对的呢？

请高人指点一下，多谢！

freegale

没人回复么？