1. Which of the following statements are true of production possibility frontiers and trade between nations? I. Nations specialize and trade based on com- parative advantage in production. II. Free trade allows each nation to consume beyond the production possibility frontier. III. The flow of goods and services is based on the principle of absolute advantage. IV. Nations can consume at points beyond the production possibility frontier by protecting domestic industries from free trade. A. I and II only B. II and III only C. III and IV only D. I, II, and III only E. I, II, III, and IV