A Progressive Ratio PR schedule is a type of schedule of reinforcement where the response requirement systematically increases after a fixed number of reinforcers are earned The defining characteristic and crucial point of a PR schedule is that the increase in the response requirement is independent of the learners rate of responding or their successful completion of trials within that specific block Its purpose is often to assess the breaking point of a reinforcer meaning how much effort an individual will expend for a given reinforcer Gatsbys plan to increase the requirement based on client earns reinforcement three times in a row makes the schedules progression dependent on the clients performance and reinforcement history This directly contradicts the core definition of a PR schedule where the progression is predetermined and applied irrespective of the clients success within the ongoing ratio Option A is incorrect because an initial requirement of 3 eg FR3 is typically not considered too high Option C is incorrect the increment size depends on the specific research question or assessment goal Option D while important for practical and ethical reasons is not the primary conceptual error related to the fundamental definition of how a PR schedule progresses