问题
pulation of Chongqing, _____from the countryside, are making their efforts to build their hometown into a more beautiful and modern society.
A:the majority of which are
B:of which the majority is
C:the majority of whom are
D:of whom the majority is;
B:of which the majority is
C:the majority of whom are
D:of whom the majority is;
正确答案是：
