Mandy has a habit of buying lottery tickets every day. She won her first lottery when she was a freshman in college. Three months after her first win, she won another lottery. She won her third lottery two years later when she was a junior. She wants to stop buying tickets but cannot resist doing so as her winnings act as reinforcement for her buying behavior. In the context of operant conditioning, which of the following reinforcement schedules do the lottery winnings illustrate?

A. a variable-interval schedule

B. a fixed-ratio schedule

C. a variable-ratio schedule

D. a fixed-interval schedule

C. a variable-ratio schedule

Explanation:

Variable-ratio schedule: In psychology, the term "variable-ratio schedule is described as one of the different reinforcement schedules which are considered as one of the important parts in the operant conditioning theory and were proposed by B. F. Skinner. In a variable-ratio schedule, a specific response is being reinforced after an "unpredictable number" of particular responses. However, it is often considered as creating high rate yet steady responding.

Example: Lottery and gambling.

In the question above, the given statement represents a variable-ratio schedule.