The marginal product of labor is 110 cups for the first worker, 90 cups for the second worker, and 70 cups for the third worker. The MPL declines due to the principle of diminishing returns to labor. The marginal product of labor is 110 cups for the first worker, 90 cups for the second worker, and 70 cups for the third worker. The MPL declines due to the principle of spreading the overhead. The marginal product of labor is 70 cups for the first worker, 90 cups for the second worker, and 110 cups for the third worker. The MPL increases due to the principle of diminishing returns to labor. The marginal product of labor is 110 cups for the first worker, 70 cups for the second worker, and 90 cups for the third worker. The MPL declines due to the principle of diminishing returns to labor.1. What is the marginal product of the first worker, the second worker, the third worker? 2. Why does the marginal product of labor (MPL) decline as the number of workers increases?