1. Elk now live almost solely in the Rocky Mountains, which would make it seem that elk are mountain dwellers, while   which不能指代句子肯定不对
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  用词错误，still 多余
4. Now living almost solely in the Rocky Mountains, it would seem that elk were mountain dwellers, although  VING置于句首，后面应紧跟其修饰对象

5. It seems that elk would be mountain dwellers from the fact that they now live solely almost in the Rocky Mountains, since 连词错误，不合句意，from the fact that 感觉不妥

答案是A，我觉得选B，请大家帮忙看看

they are mountain dwellers

但是B 中的they 这的代词指代肯是不如A清楚的

而且B 的主语变成了the fact,  but 后面的并列也不是很好了

查了金山词霸，elk的复数形式可以是elk 或elks这里说mountain dwellers从逻辑意思上来说只能是elk 不可能是 Rocky Mountains所以they refers to elk

请大家讨论

支持A.

因为A中就只有一处不妥:which的指代问题.
而B有两处不妥:
① they are mountain dwellers中的they指代不清,可以是the Rocky Mountains或elk
②The fact that elk now live almost solely in the Rocky Mountains would make it seem that they are mountain dwellers, but they once ranged over virtually all of the continental United States except for a small strip in the extreme Southwest. 句中是红字部分与兰字部分对比，从结构上看这两部分可以都是seem的从句，此时一个事实说明了两个截然相反的事实．这个问题在A中就没有，因为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. 句中红字部分与兰字部分对比，which...是红字部分的定语从句，结构很清楚．

可是SC已经考了太多的which指代紧跟先行词的考点啊；

而且but可以是conj.，前面加一个逗号，就可以像and一样，另外起一个与the fact that 并列的句子，所以可以认为意思上没有矛盾；

还是B好些；