At a Conference a Researcher Reports Prevalence Rates for Personality

At a conference a researcher reports prevalence rates for personality disorders. Several audience members conclude that these figures are lower than those reported in the literature. During a question-and-answer period, which of the following is likely to be viewed as a reason for this discrepancy?

A) The researcher relied on a psychodynamic model of the etiology of personality disorders.
B) The researcher failed to consider the impact of mental retardation on the prevalence of these disorders.
C) The researcher failed to obtain records of physiological functions that can often reveal otherwise hidden pathology.
D) The researcher used self-report instruments to estimate prevalence of disorders seen in people with little awareness of their behavior.