GWD30-41

Please take a quick look at the question below.

The key is A, while in GMAT, I don't think "which" can represent a sentence. This has been mentioned a couple of times in Prep_SC_notes_By findjuhl-21th. Please advice. Thanks. 

Q41:

Elk now live almost solely in the Rocky Mountains, which would make it seem that elk are mountain dwellers, while they once ranged over virtually all of the continental United States except for a small strip in the extreme Southwest.

1. Elk now live almost solely in the Rocky Mountains, which would make it seem that elk are mountain dwellers, while

2. The fact that elk now live almost solely in the Rocky Mountains would make it seem that they are mountain dwellers, but

3. It would seem that elk would be mountain dwellers because of their living now solely almost in the Rocky Mountains, but still

4. Now living almost solely in the Rocky Mountains, it would seem that elk were mountain dwellers, although

5. It seems that elk would be mountain dwellers from the fact that they now live solely almost in the Rocky Mountains, since

1. Elk now live almost solely in the Rocky Mountains, which would make it seem that elk are mountain dwellers, while

2. The fact that elk now live almost solely in the Rocky Mountains would make it seem that they are mountain dwellers, but

3. It would seem that elk would be mountain dwellers because of their living now solely almost in the Rocky Mountains, but still

4. Now living almost solely in the Rocky Mountains, it would seem that elk were mountain dwellers, although

5. It seems that elk would be mountain dwellers from the fact that they now live solely almost in the Rocky Mountains, since

which不能指代句子，这种说法要分情况，绝大多数都是对的，但不能完全否定

这就是为什么sc没有一个万能的法则

then, under what circumstances can it refer to a sentence?

thanks