企业年金计划的出现早于社会养老保险计划，现在则被视为养老保险体系中的（）

A、首要内容

B、第二支柱

C、必须补充

D、强制延神

What is the woman’s problem

A．She did not enroll on time.

B．She failed to attend the first few classes.

C．She must miss the start of the semester.

D．She doesn’t have regular Internet access.