Answer: The smallest possible incentive
Step-by-step explanation:
The incentive plan can boost the working performance of the employee in an organization. It does not matter whether the incentive plan is small or big, it technically encourage and motivate the employees for the participation in the incentive program plan.
According to the question, the manager wants to improve the working performance of their subordinates by using the social psychology knowledge.
Therefore, the manager decided to use the possible incentive plan to motivate their subordinates.