Answer:
d. token economy
Explanation:
Token economy: In psychology, the term token economy is defined as a phenomenon which is based on the contingency management related to the systematic reinforcement of specific target behavior. It is considered as a reward for some good behavior with specific tokens that an individual can exchange with things that are desirable for him or her. A token can be anything, for example, sticker, chip, coin, etc.
Token economy is generally based on the ABA or applied behavioral analysis principles.
In the question above, the given statement states that Shay is using a token economy.