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

(A) Same
(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 sizable population of wolves and where

Verbal Review explanation says - the sentence makes two points about Minnesota. The same word should introduce each point. Hence E is the correct choice.

My question - Is A or C grammatically incorrect? Also I didn't pick E because I feel it was not as concise as A or C.

Can someone shed some light?

Thanks

As is indicated (although not as directly as it could be) in the OG explanation, parallelism is the deciding factor here. Both choices A and C introduce one of the two paired clauses with 'that', but then turn around and introduce the other with 'where'. That's bad parallelism, rendering both of those choices inferior to choice E (which, while longer, has good parallelism).