John Has Worked at His Employer's for an Amazing 36

John has worked at his employer's for an amazing 36 years.He has been a car sales manager for the past 11 years.He has noted that whenever he insists his sales people set goals,they achieve a higher level of sales.He has concluded that the reason for this is because

A) the sales people believe it is a strategy to see who is the most competent to fill John's position when he retires.
B) the sales people try harder because they are not given training.
C) the sales people set unrealistic goals that in turn cause them to work harder.
D) stated goals direct attention to reach those goals.
E) the sales people like to see and compare themselves to the other sales people.