The importance of conversion disorders in psychoanalysis is based upon:

a) Freud's discovery that patients with conversion disorders were usually victims of sexual abuse.
b) Freud, who suffered from and overcame a conversion disorder.
c) Freud's belief that more directive methods were appropriate for treating conversion disorders, paving the way for linking psychoanalysis and behaviour therapy.
d) Freud's development of many psychoanalytic concepts while treating patients with conversion disorder.

d