请教885-7-4

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) because they live

为什么答案是C,而A和D不可以呢?

A D的逻辑主语有问题的。而且，即使这两个选项有正确的逻辑主语，应该以没有C好。