[单选]Competitive markets are characterized by
A. a small number of buyers and sellers.
B. unique products.
C. the interdependence of firms.
D. free entry and exit by firms.
[单选]For a firm operating in a competitive industry, which of the following statements is not correct?
A. Price equals average revenue.
B. Price equals marginal revenue.
C. Total revenue is constant.
D. Marginal revenue is constant.
[单选]Suppose that in a competitive market the equilibrium price is $2.50. What is marginal revenue for the last unit sold by the typical firm in this market?
A. less than $2.50
B. more than $2.50
C. exactly $2.50
D. The marginal revenue cannot be determined without knowing the actual quantity sold by the typical firm.