Answer and explanation:
An oligopoly is when the market is controlled by a small group of two or more companies. Oligopoly firms may consent to market collusion, and build obstacles to new trade entry. If the businesses do not, they will be forced to lower their prices and open the markets to new and smaller firms.
Supermarkets are oligopolies because in every market there are a few companies offering the same products just like them with small differentiation between one and another, providing those goods to relatively similar prices.
