There are 104 elements found in nature are metals.A. most of itB. thatC. most of whichD.

问题补充：

There are 104 elements found in nature, are metals.

A. most of it

B. that

C. most of which

D. mostly

答案：

A. most of it

B. that

(答案→)C. most of which

D. mostly

解析：most of which引导非限制性定语从句。