Consider the following statements when answering this question: I. If the marginal product of labor increases whenever more labor is used, and labor is the only factor of production used by the firm, than then marginal cost of production is decreasing. II. If labor obeys the law of diminishing returns, and is the only factor of production used by the firm, then marginal cost of production is increasing. A) I is true, and II is false. B) I is false, and II is true. C) I and II are both true. D) I and II are both false.