The Marginal Product of an Additional Unit of Labor Is

The marginal product of an additional unit of labor is 100 units per day and the market price of this output is $0.75 per unit.
-If the cost to the firm of hiring this unit of labor (wages,Social Security,and other payroll taxes) is $12 per hour for an eight-hour day,a profit-maximizing firm

A) should hire the additional unit of labor.
B) should not hire this extra unit.
C) should hire this person for half a day.
D) should hire this extra unit of labor plus one more.
E) There is not enough information available to determine the optimal number of workers.