Suppose that the marginal benefit of having a security guard at the airport is MB1,at the bank is MB2,and at the mall is MB3.The marginal cost of assigning security guard is the same for all three places,and it is represented by MC2. Suppose all three locations hire the efficient number of guards,and that the marginal cost of having a security guard equals his or her wage.Efficiency would also require that A)all security guards be paid the same wage regardless of where they work. B)more security guards be hired at the location at which marginal cost is lowest. C)more security guards would be hired at the location at which marginal cost is greatest. D)security guards at the airport be subsidized because private markets will under-provide them.