Final answer:
The Premack Principle posits that engaging in a preferred activity can be used as a reward to reinforce a less preferred task. It is correctly demonstrated when a teacher rewards a child after completing a complex task with an activity they enjoy, making the statement (a) True.
Step-by-step explanation:
The Premack Principle states that more probable behaviors, or activities that individuals find enjoyable, can be used as rewards to reinforce the completion of less probable behaviors, or tasks that they find less desirable. In the context of the question, the premise is that a teacher uses a reward to increase the likelihood of a child completing a complex task. This is a true application of the Premack Principle. Consider this scenario: a student is more likely to engage in gaming than completing homework. The teacher uses gaming time as a reward for the student who completes their homework.
This application of the Premack Principle suggests the student's behavior of completing homework can be increased by the opportunity to engage in a more desired activity (gaming) as a consequence of finishing the homework. Effectively, a less preferred but necessary behavior is reinforced by the promise of a more preferred behavior. This principle is supported by empirical evidence showing the efficacy of positive reinforcement when applied to learning and behavior modification, which aligns with the theories proposed by Skinner on operant conditioning.