Short-run marginal costs for firms "A", "B" and "C" are given by SMC = 2qA, SMC = 4qB andSMC = 2qC respectively. Assume that these firms behave under the rules of perfect competition. Using diagrams, derive the market supply curve for this industry. Market demand is given by D= 120 - 2.75p. Solve for equilibrium price, equilibrium quantity and the quantity supplied by each firm.