Final answer:
An example of a positive reinforcer is d) getting an extra day off school for perfect attendance.
Step-by-step explanation:
A positive reinforcer is something that increases the likelihood of a desired behavior occurring again. An example of a positive reinforcer from the options given would be option d)getting an extra day off school at the end of the year for perfect attendance.
This is a reward that is added to encourage the behavior of attending school regularly. Positive reinforcers can include things like praise, rewards, and privileges that increase the likelihood of a behavior being repeated.