4. [30 marks] Consider the equilibrium in a monopolistically competitive market depicted in Figure 2. Figure 2. a. Explain why the relationship between the industry's average cost and the number of rms in the industry, labeled CC in Figure 2, is upward sloping. b. Explain why the relationship between the industry's price and the number of rms in the industry, labeled PP in Figure 2, is downward sloping. c. How would international trade affect Figure 2? What are the channels for the gains from trade