There are 900 students in our school, ________ 40％ are girls.

There are 900 students in our school, ________ 40％ are girls.

A.of which

B.of whom

C.of them

D.in them

答案及解析： B

解析：

students是先行词。如两句间是句号，应选C，且of要大写首字母。