Trichotillomania, a psychiatric condition in which afflicted individuals compulsively pull out their own hair, is of special interest for future research in human motor control because

A) Movement data from bald people are probably less hairy than movement data from hairy people
B) A genetic mutation has been found to underlie trichotillomania
C) The hand and finger movements of trichotillomaniacs are probably no different from those of other people
D) a and c