Graphically, We Can Think of the Marginal Product of a Factor

Graphically, we can think of the marginal product of a factor as the:

A) slope of the total production curve, when output is plotted against the quantity of the input that is used.
B) slope of the total cost curve, when output is plotted against the costs of the quantity of the inputs used.
C) additional cost associated with producing one more unit of output.
D) additional inputs associated with producing one more unit of output.