Final answer:
The scenario in the question illustrates the application of d. the token economy in an eating disorders clinic.
Step-by-step explanation:
The best application that the scenario in the question illustrates is the token economy. In an eating disorders clinic, patients receive merits (tokens) for good eating behaviors such as finishing their meal, not exercising after their meal, and exhibiting appropriate behaviors on the unit. These tokens can then be exchanged for rewards and prizes. This system of using tokens as secondary reinforcers, and building an entire behavior management system around them, is called a token economy.