Dr. Middleton is reevaluating his use of drugs and psychotherapy when working with clients suffering from anxiety or depression. If Dr. Middleton wants to take a conservative strategy, he should begin with ____ and then add or switch to ____ if necessary only.

a. behavior modification; anxiolytic drugs
b. anxiolytic drugs; behavior modification
c. drug treatment; interpersonal psychotherapy
d. interpersonal psychotherapy; drug treatment