Their problem today is somewhat similar to they faced many years ago. A. thatB. which C.

问题补充：

Their problem today is somewhat similar to they faced many years ago.

A. that

B. which

C. that which

D. it

答案：

A. that

B. which

(答案→)C. that which

D. it

解析：

C。that which相当于 the problem which。