Caribou are wary animals with excellent hearing, so stalking them over the treeless landscape, getting close enough to kill it with nothing but a handheld lance, as Dorset people did, required exceptional hunting skill.

A.  so stalking them over the treeless landscape, getting close enough to kill it

B.  so to stalk them over the treeless landscape and get close enough to kill one

C. so in order to stalk them over the treeless landscape and get close enough to kill one

D. and so in order to stalk it over the treeless landscape, getting close enough to kill it

E.  and so stalking them over the treeless landscape and getting close enough in order to kill it

答案是B   看不懂啊~~~ 麻烦分析一下句子结构。。。。。

主句: Caribou are wary animals with excellent hearing
从句: so to stalk them over the treeless landscape and get close enough to

kill one with nothing but a handheld lance, as Dorset people did, required

exceptional hunting skill.

从句主语: to stalk them over the treeless landscape and get close enough to

kill one with nothing but a handheld lance
从句谓语: required
从句宾语: exceptional hunting skill