One of the Major Problems with Using Employee Referrals as a Source

One of the major problems with using employee referrals as a source of new employees is:

A) the high turnover of staff in organisations today works against loyalty.
B) current staff may not know what the requirements are for new positions.
C) that they may be considered discriminatory if they maintain the present employee mix.
D) the possibility of new employees not adapting to the culture of the business.