A perfectly competitive firm is faced with a horizontal, perfectly elastic demand curve because单项选择题

a. all firms sell homogeneous products so, in theory, a firm would sell nothing if it raised the price higher than market price.

b. there are very strong barriers to entry and exit.

c. there are no substitute products, so all firms sell at the same price.

d. firms have a high level of market power, so they can sell any quantity at the market equilibrium price.