Answer:b) the employer pays his employees year end bonus according to how the business does and his observation of the employees efforts
Explanation: The best payment system to overcome moral- hazard problem by employers is to pay by piece rates.
Piece rates or payment by result system is a payment system where employees are paid in proportion to the efforts and the overall business performance. With this system both employees and employers will be satisfied with the outcomes and will in turn prevent any suspicions from the employees since the system is clearly understood by both parties and a mutual relationship we be created.