Dede is plagued by fears of having her house broken into and feels compelled to repeatedly check and recheck the already locked doors and windows. A therapist suggests that her compulsive checking has become so persistent because it temporarily relieves her anxiety. This suggestion highlights the impact of ________ on Dede's compulsive behavior. 

a) stimulus generalization 

b) observational learning 

c) reinforcement 

d) epigenetics