If a Firm Hires 312 Workers It Produces 4,522 Computers

If a firm hires 312 workers it produces 4,522 computers. If it hires 313 workers it produces 4,786 computers. If computers sell at a constant price of $1 and labor is hired at a constant wage rate of $65 per worker

A) the firm should hire and retain the additional worker.
B) the marginal factor cost of labor is $65.
C) the marginal revenue product of the added worker is $264.
D) all of the above
E) the additional employee brings into the firm a NET revenue of $112.