Gary Has Been Diagnosed with Pre-Diabetes and His Dietician Has

Gary has been diagnosed with pre-diabetes and his dietician has suggested that he reduce the number of sugary snacks he consumes each day. To reduce his temptation to buy and consume these snacks Gary starts shopping at a local farmer's market and subscribes to a healthy eating blog. Gary's behavior demonstrates principles of a:

A) stimulus-control intervention.
B) contingency contract.
C) relapse prevention program.
D) self-monitoring program.