关于逗号的问题

225. Minnesota is the only one of the contiguous forty-eight states that still has a sizable wolf population. and where this predator remains the archenemy of cattle and sheep.

(A)  that still has a sizable wolf population, and where

(B)  that still has a sizable wolf population, where

(C)  that still has a sizable population of wolves, and where

(D)  where the population of wolves is still sizable;

（E）where there is still a sizable population of wolves and where

答案E

这题想请教C，C这里加了逗号不影响后面定语从句的并列吧？只是THAT引导没有where引导显的对称是吗？假如C改成where there is still a sizable population of wolves， and where算错吗？