Which Statement Best Describes the Importance of a Therapist's Sex

Which statement best describes the importance of a therapist's sex

A)  The sex of the therapist only matters if the client thinks it matters. 
B)  Female therapists tend to be more effective, perhaps because they are more nurturing toward their clients. 
C)  Clients should choose a therapist who is of the same sex as themselves. 
D)  Male therapists are more effective for very difficult-to-treat clients.