The patent of "Miracle Drug" by a US drug maker(X) has just expired. Now generic drug makers are ready to enter the market.

Answer the following questions:

1. Since the time when the patent was granted until the time when the patent expired, How the US drug maker (X) Maximized profit (or minimized losses)?

2. After the patent expired and more generic drug makers joined the market for "Miracle Drug" what would you say the market structure could change into? Choose one among perfect competition, monopolistic competition, Oligopoly and monopoly. Why? Justify your answer

3. Compare the price and output determination of the US drug maker before and after the patent expiration?

4. Discuss how this market structure change can affect the drug maker's profit (or loss) in the short run and long run.