Final answer:
Matt's association of happiness with the afternoon time of three o'clock due to the end of the school day is an example of classical conditioning.
Step-by-step explanation:
In the scenario described, Matt has learned to associate the specific time of the afternoon—three o'clock, with feelings of happiness due to the end of the school day. This type of learning is an example of classical conditioning, which is a learning process that occurs when two stimuli are repeatedly paired; a response that is at first elicited by the second stimulus is eventually elicited by the first stimulus alone. In Matt's case, the time of day (three in the afternoon) has become a conditioned stimulus that elicits happiness, a conditioned response, because it has been paired with the unconditioned stimulus (school ending), which naturally elicits the unconditioned response (happiness).