A Computer Services Center Has a Problem with "Malicious" Computer

Multiple Choice

A computer services center has a problem with "malicious" computer usage.The center's director has decided to hire additional personnel to monitor computer usage.In order to maximize the net benefit from hiring monitors,the director should hire the number of monitors at which

A) the marginal revenue from the last monitor equals the marginal cost of the last monitor.
B) the decrease in the cost of malicious usage from the last monitor hired equals the cost of hiring the last monitor.
C) the marginal benefit per dollar is equal across monitors.
D) both b and c
E) all of the above