Final answer:
The food pellet is an unconditioned reinforcer and the tune is a conditioned reinforcer due to the association the rat makes between them through classical conditioning.
Step-by-step explanation:
If you train a rat to receive a food pellet every time you play a particular song, the food pellet is the unconditioned reinforcer, and the tune is the conditioned reinforcer. The correct answer is B) Unconditioned reinforcer; conditioned reinforcer. This is because the food pellet provides an automatic positive response, which is why it is an unconditioned reinforcer. The tune of the song, on the other hand, starts out as a neutral stimulus and only becomes reinforcing after it is associated with the unconditioned reinforcer (the food). Over time and through repetition, the rat learns to associate the tune with the food, which is an example of classical conditioning.