A. Earning an "A" despite not studying or listening in class B. Receiving a "thank you" from somebody after doing something nice C. The inability to get a job due to prior criminal history D. Refusing to leave a tip for service that was bad
Since reinforcing is the result or relapse of a prior event, it would have to be C. Not getting a job due to past history is reinforcement of his actions and what they resulted in.
