The introduction of a pleasant stimulus is to ________ as the withdrawal of a pleasant stimulus is to ________.

A) positive reinforcer;negative reinforcer
B) immediate reinforcer;delayed reinforcer
C) reinforcement;punishment
D) primary reinforcer;secondary reinforcer

The introduction of a pleasant stimulus is known as positive reinforcement, which falls under the category of reinforcement. This means that the behavior is more likely to occur in the future. On the other hand, the withdrawal of a pleasant stimulus is known as punishment, specifically negative punishment or the removal of a positive reinforcer. This means that the behavior is less likely to occur in the future. Therefore, choice C, reinforcement and punishment, is the best choice as it accurately describes both scenarios.