Complete the following table, where L is units of labor, Q is units of output, and MP is the marginal product of labor. L Q MP VC TC MC ATC 0 0 0 $ 0 $12 $ 0 $__ 1 6 6 3 15 .50 ___ 2 15 9 6 30 ___ ___ 3 21 6 9 ___ ___ 4 24 3 12 ___ ___ ___ 5 26 2 15 ___ ___ ___ a. At what level of labor input do the marginal returns to labor begin to diminish? b. What is the average variable cost when Q = 24? c. What is this firm's fixed cost? d. What is the wage rate per day?