A Major Reason for the Lack of Popularity of Freud's

A major reason for the lack of popularity of Freud's theory of sexuality among American sex researchers is

A) the emphasis on unconscious forces such as libido.
B) his overemphasis on adolescent and adult sexual expression.
C) the fact that there were no empirical data to support his ideas.
D) his view that excessive masturbation is the root of many personality problems.