Answer:
C.
One ethnic group was almost eliminated.
Explanation:
This is an absolute address of a place, which means that you can find this address without knowing anything else, such as addresses of other places. (so the answer is: absolute address or absolute location of a place)
Another kind of address would be be a relative address, such as "to the left of the school"
River valley trade made them key economic areas.
Hope this helped. :)
