53 and 54 I don't understand at all what are the answers and can you explain?

53) Suppose the market for AR-15 style rifles in the United States was in an initial long-run equilibrium. In the fall of 2012, the demand for these rifles increased substantially due to 53) concerns that President Obama would either ban or restrict the sale of these semi-automatic rifles. As a result, the market price of these rifles increased, and gun manufacturers earned positive economic profits (shown in the figure below). Cost Curves and Firm Demand for Representative U.S. AR-15 Market for AR-15 Rifles in Manufacturer United States p Market Demand after change in expectations of future AR-15 Availability, Fall 2012 Initial Market Supply Fall 2012 p = MR Short Run Profits: PFall 2012 Initial (p - ATC)q p = MR P Initial Initial Market Demand 9initial 9 Fall 2012 Finitial 9 Fall 2012 The presence of economic profits in the short-run will lead to the A) exit of existing firms from the industry and cause the market demand curve to shift in until the final market price equals the minimum of the average total cost for the representative firm B) exit of existing firms from the industry and cause the market supply curve to shift in, raising profits for existing firms C) entry of new firms and cause the market supply curve to shift out until the final market price equals the minimum of the average total cost for the representative firm D) jentry of new firms and cause the market demand curve to shift in until the final market price equals the minimum of the average total cost for the representative firm 54) Suppose ethanol is produced in a perfectly competitive market. If a subsidy is paid to ethanol 54) producers, the ethanol producers' profit will A) increase in the short run but reduce to zero in the long run B) increase in the short run but become negative in the long run decrease in the short run but reduce to zero in the long run ) increase in the short run and in the long run