The Premack Principle often referred to as Grandmas Rule states that a highprobability behavior a preferred activity can be used as a reinforcer for a lowprobability behavior a less preferred activity It involves making access to the preferred activity contingent upon the completion of the less preferred activity In this case helping the teacher is Alberts highprobability behavior and initiating peer interactions is his lowprobability behavior Option B correctly applies the Premack Principle by making access to the preferred activity helping the teacher contingent on the performance of the less preferred activity social initiations with peers Option A is a form of general positive reinforcement but it doesnt utilize the contingency inherent in the Premack Principle Option C describes a token economy which is a different behaviorchange system although it can incorporate preferred activities Option D is an aversive approach that involves blocking access without a clear contingency for the desired behavior and it does not represent the Premack Principle it could even be considered a form of punishment or deprivation which may have negative side effects