一道英语单选题

一道英语单选题
1．The population of the village near sea,（ ）are making their efforts to develop economy of their own.
A nearly seventy percent of which depend on fishing
B． of which nearly seventy percent depends on fishing
C.nearly seventy percent of whom depends on fishing
D．of whom nearly seventy percent depend on fishing
我想问A为什么不可以!
population,人口,又不是人,怎么能用of whom呢?