问题详情

What does the word " That" refer to in the last sentence in Paragraph 6？

A．The troubling business model of for-profit colleges.

B．Paying special attention only to for-profit colleges.

C．Introducing the new "gainful employment" rule.

D．The shabby marketing of all the colleges.

请帮忙给出正确答案和分析，谢谢！