Cameron, a Supervisor at Margolia Co

Cameron, a supervisor at Margolia Co., needs to appraise the performance of her subordinate, Stefan. In the context of performance information, what is the least biased source of information for appraisal and why?

A) Peers because they often understand an employee better than superiors.
B) Managers because their success depends on the employee's productivity.
C) Customers because employees are often directly in contact with them.
D) Subordinates because the power relationships motivate a subordinate to provide honest information.
E) The employee himself because there is generally better agreement between an employee and his or her supervisor.