As Applied to Labor Demand,the Marginal Approach to Profit

As applied to labor demand,the marginal approach to profit

A) is irrelevant
B) requires setting marginal cost equal to the wage rate
C) requires setting marginal revenue equal to the wage rate
D) says that a firm should increase employment if doing so adds more to revenue than it adds to cost
E) says that a firm should decrease employment if doing so adds more to cost than it adds to revenue