Which statement(s) is true? The concave shape of the production possibilities frontier implies that the opportunity cost of each good is increasing in the level of output of that good. The concave shape of the production possibilities frontier implies that the opportunity cost of each good is decreasing in the level of output of that good. The slope of the production possibilities frontier is the opportunity cost of producing an additional unit of a good in terms of the other good. The convex shape of the production possibilities frontier implies that the opportunity cost of each good is increasing in the level of output of that good. Group of answer choices only 1 is true only 2 and 3 are true only 1 and 3 are true only 3 and 4 are true only 4 is true