Answer:
a. Purely competitive
b. Monopolistic Competition
c. Monopolistic Competition
d. Oligopoly
Explanation:
a. Corn farming is a purely competitive market as there is a large number of producers selling the homogenous good i.e corn.
b. Grocery stores are an example of monopolistic competition as there is a large number of sellers providing differentiated products.
c. Electric companies are also an example of monopolistic competition as there is a large number of companies providing differentiated products.
d. Automobile manufacturing is an oligopoly market, there are few large firms dominating the market. These firms are producing slightly differentiated products and are interdependent.
