Which of the following is the most challenging for the work of counseling services?
A.More and more college students suffer from mental-health problems.
B.Though many students have mental-health problem, few of them seek counseling.
C.They have to keep an eye out for students who might pose a risk to others.
D.Persuade people into believing what"s made into the media isn"t very popular.
请帮忙给出正确答案和分析,谢谢!