Final answer:
The type of operant conditioning in this scenario is positive reinforcement.
Step-by-step explanation:
The type of operant conditioning in this scenario is a) Positive reinforcement. Positive reinforcement occurs when a behavior is followed by the addition of something desirable, which increases the likelihood of that behavior being repeated. In this case, finding a loonie in the coin return slot of a pop machine is a pleasant consequence and serves as a reward, leading to the behavior of checking other pop machines over the next few days.