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The table below shows wa firm's hourly level of output changes as more 1 point of the labor input is employed. The firm sells its output and hires labor in perfectly competitive markets. I he wage paid to labor is $10 per hour, and the price of the firm's output is $2 per unit. Based on the data in the table, the marginal revenue product of the fourth hour of labor is equal to Hours of Labor Marginal Product O 10 12 O $7 $14 O $70 O $4 $26