B; As far as the relation between humans and the environment, it is obvious how much they relied on it. Not only as a food source, but for economic growth and sustainability as well. The other answers make valid points but in the context of this question, the only one that even mentions the relation is B.
Answer:
I think it's the Himalayan region.
the answer is a
(context) There was an abundance of trees along riverbanks where sawmills were established.
(more context) I also took the test
