Why does the marginal product of labor eventually decline as more labor is used with another fixed input? A. The labor will have, on average, fewer units of the other inputs to combine with and the increases to total output obtained from more labor will increase. B. The labor will have, on average, more units of the other inputs to combine with and the increases to total output obtained from more labor will increase. C. The labor will have, on average, more units of the other inputs to combine with and the increases to total output obtained from more labor will decrease. D. The labor will have, on average, fewer units of the other inputs to combine with and the increases to total output obtained from more labor will decrease.