Answer:
variable-interval
Explanation:
Variable-interval schedule: In psychology, the term "variable-interval schedule" is described as a schedule of reinforcement that occurs in the operant conditioning theory. In the variable-interval schedule, a specific reinforcement is being given to a particular response only after a specific time has been passed (unpredictable time), yet this time is being kept on a variable/changing schedule.
In the question above, Lila instructor is testing her on a variable-interval schedule.
