The problem in today’s parenting environment is many believe it is their job to solve all

问题补充：

The problem in today’s parenting environment is many believe it is their job to solve all their children’s problems.

A. who

B. that

C. which

D. What

答案：

A. who

(答案→)B. that

C. which

D. What

解析：本题考查名词性从句。题中表语从句中不缺少成分，故用关系词that，选B。