Which one is the disadvantage of “employee referral program”?

Which one is the disadvantage of “employee referral program”?
A.Rejections may produce discontent; telling them why you rejected them and what modificatory actions they might take is crucial
B.Knowing a candidate’s strengths and weaknesses
C.Inside candidates may require less orientation and (perhaps) training than outsiders
D.Current employees may also be more committed to the company
正确答案：Rejections may produce discontent; telling them why you rejected them and what modificatory actions they might take is crucial