With Regard to Sampling Bias, All but Which of the Following

Multiple Choice

With regard to sampling bias, all but which of the following has been raised as a concern?

A) Research has ignored many of the people most in need of counseling services.
B) Sampling has included a disproportionate representation of the sexes.
C) The validity of the DSM's personality disorders is strong.
D) Sampling bias raises questions about who has the power to define illness and, thus, social control.