4. The aluminum industry is perfectly competitive, and each producer has a total cost function TO(Q) = 190 - 8Q2 + Q3. The market demand is D(P) = 70 - 2P. (a) What are the long-run marginal and average cost functions? (b) What is the long-run equilibrium price in the mar- ket, and how much will each firm produce in equi- librium? (c) How many firms are in the aluminum market in a long-run perfectly competitive equilibrium, and how much aluminum will be supplied by all producers in the market