Which of the Following Describes the Marginal Product of Labor

Which of the following describes the marginal product of labor?

A) It is the additional amount of consumer goods that can be bought from an additional hour's worth of work.
B) It is the additional amount of inputs a firm demands based on a change in consumer demand for the output.
C) It is the additional amount of output that can be produced from hiring one more worker.
D) It is the decreasing amount of output that can be produced from hiring one more worker.
E) It is the value of production from the last worker hired.