In Sam's greenhouse operation, labor is the only short term variable input. After completing a cost analysis, if the marginal product of labor is the same for each unit of labor, this will imply that
A. the average product of labor is always equal to the marginal product of labor.
B. the average product of labor is always greater that the marginal product of labor.
C. the average product of labor is always less than the marginal product of labor.
D. as more labor inputs are used, the average product of labor inputs will fall.