A six-year-old patient with autistic spectrum disorder has not responded to six months of psychosocial interventions and continues to demonstrate aggressive tendencies toward a younger sibling. The psychiatric-mental health nurse practitioner prescribes: a) carbamazepine (Tegretol) 200 mg once a day. b) haloperidol (Haldol) 2 mg once a day. c) risperidone (Risperdal) 0.25 mg once a day. d) venlafaxine ER (Effexor XR) 37.5 mg once a day.)