Final answer:
Trey's supervisor used coercive power by putting him on probation due to customer complaints, which is a form of punishment intended to correct behavior.
Step-by-step explanation:
Trey's supervisor was using coercive power when he was put on probation for a string of customer complaints about his service and professionalism. Coercive power is the ability of a manager to punish their employees. This can include formal punishments such as probation, demotion, or termination, as well as less formal actions like withholding of privileges or the introduction of unpleasant working conditions. In this scenario, the supervisor's action of placing Trey on probation serves as a deterrent to poor performance and is intended to correct his behavior.