When Mason was only nine years old, his two older sisters told him scary stories about vampires while he was in a dark room. As an adult, Mason is still afraid of the dark. Based on classical conditioning principles, a behavioral therapist would suggest the fear that Mason felt when his sisters told him the scary stories was an:

a. an unconditioned stimulus
b. an unconditioned response
c. a conditioned stimulus
d. a conditioned response

B