Which example illustrates an oligopoly market structure in early American history?

Answer: Two cobblers in town control the shoe making business

Explanation: Monopolists and Oligopolists exhibit peculiar behavior. A common practice when few companies have much market power is cartel or collusion. In this case, the dominant firms, instead of competing with each other, make deals to boost their profits, sacrificing economic efficiency. It is also common for firms with high market power to use this advantage to prevent new companies from entering. Thus market power is used to create barriers to entry, and these barriers to entry increase market power.