Final answer:
An 'A' in a course acts as a secondary reinforcer because it symbolizes success and approval, which are linked to more immediate primary reinforcers such as pride and satisfaction.
Step-by-step explanation:
Earning an "A" in a course is an example of a secondary reinforcer. A secondary reinforcer, such as praise, money, or high grades, has no inherent value by itself and only has reinforcing qualities when linked with something else like a primary reinforcer. In the context of operant conditioning, these secondary reinforcers are powerful tools for shaping behavior as they are related to more immediately gratifying primary reinforcers like food or pleasure. In the case of an "A" in a course, it is a symbol of success and approval which can be linked to the primary reinforcers of pride, satisfaction, and the opening of future opportunities like career advancement.