Answer:
variable-interval
Explanation:
Variable-interval schedule: The variable-interval schedule is one of the types of reinforcement schedule in operant conditioning. In this reinforcement schedule, reinforcement is given to a particular response when a specific time has been passed, and the time is on variable or varying schedule.
The variable-interval schedule gives rise to a steady, and slow response rate.
In the question above, holding is reinforced on a variable-interval schedule.
