A firm's production process uses labor, L, and capital, K and materials, M, to produce an output, Q according to the function Q=KLM, where the marginal products of the three inputs are MPL=KM,MMK=LM, and MPM=KL. The wage rate for labor is W=2, the rental rate of capital is r=1, and the cost of materials is m=4 per unit, Let materials input be foxed now at M=2. What is the cost minimizing level of capital that the firm must use to produce a target ievel of output, Q=8000 : A. 60 3. 10 C. 20 D. 40 Reset Selection Mark for Review What's. This?.