Assume a Firm Is Currently Employing 20 Units of Capital

Assume a firm is currently employing 20 units of capital and 100 units of labor in its production process. Assume also that the marginal product of the 20^th unit of capital is 40 units of output, the marginal product of the 100^th unit of labor is 10 units of output and the per unit prices of capital and labor are $20 and $10, respectively. In this case, in order to minimize its costs of production the firm should:

A) hire more capital and less labor.
B) hire more labor and less capital.
C) hire less capital and less labor.
D) hire more capital and more labor.