Choose a good or service that is supplied by a small number of oligopoly firms.

Choose a good or service that is supplied by a small number of oligopoly firms. Gather information on the good from public sources, library databases, etc. to answer the following questions:
a. Who are the leading firms and what are their market shares? Compute the concentration ratio for the relevant market.
b. What are the most important decisions (price, innovation, advertising and so on) on which the firms compete?
c. What has been the history of entry into the market? What kinds of barriers to entry exist?