b] David can mow four lawns in a day or plant four trees in a day. Draw David's production possibilities curve for mowing lawns and planting trees. Again, assume a linear production possibilities curve and put the quantity of lawns mowed per day on the horizontal axis. What is David's opportunity cost of planting trees? What is David's opportunity cost of mowing lawns? c) Given the production information in parts a and b above, who has the comparative advantage in planting trees? Mowing lawns