A Major Criticism of Freud's Theory Was That Most of the Information

A major criticism of Freud's theory was that most of the information he gathered came from individual case histories of his patients.Why might this have caused Freud's views to be biased?

A) Most of Freud's patients had mental problems and were not a representative sample of the population.
B) Dealing with mentally disturbed patients all day altered Freud's perception of reality.
C) All of his theories are correct and the criticism is unjustified.
D) Freud's emphasis on sexual and aggressive drives caused people to reject his theories outright.