2. [9pt] Amy, Bill, and Carla all mow lawns for money. Each of them operates a different lawn mower. The accompanying table shows the total cost to Amy, Bill, and Carla of mowing lawns. Quantity of lawns Bill's Total Cost mowed Amy's Total Cost Carla's Total Cost 0 0 0 0 20 10 N N 35 20 7 3 45 30 17 4 50 40 32 5 52 50 52 6 53 60 82 [6pt] Calculate Amy's, Bill's, and Carla's marginal costs. Quantity of lawns Amy's MC Bill's MC mowed Carla's MC 0 N 3 4 UT 6 b. [3pt]Who has increasing marginal cost, who has decreasing marginal cost, and who has constant marginal cost