Graphically, the marginal cost curve is A. a U​ shape, initially falling when the marginal product of labor is rising and then eventually rising when the marginal product of labor is falling. B. shaped like a​ hill, rising when the average cost of production is rising and then eventually falling when the average cost of production is falling. C. shaped like a​ hill, initially rising when the marginal product of labor is falling and then eventually falling when the marginal product of labor is rising. D. a U​ shape, initially falling when the marginal product of labor is below marginal cost and then eventually rising when the marginal product of labor is above marginal cost. E. a U​ shape, initially falling due to diminishing returns and then eventually rising due to division of labordivision of labor.