There are no legal limits, as there are for cod and haddock, on the size of monkfish that can be caught, a circumstance that contributes to their depletion through overfishing.

A) There are no legal limits, as there are for cod and haddock, on the size of monkfish that can be caught, a circumstance that contributes to their depletion through overfishing.

C) There are legal limits on the size of cod and haddock that can be caught, but not for monkfish, which  contributes to its depletion through overfishing.

答案是A,我选了C. C 哪里有问题呢?

a circumstance that 属于同位语表达，是优选结构；

which不能指代前面的一句话或一件事。