We know that the firm is a perfectly competitive firm because a. total revenue is constant b. the firm can vary the quantity it sells without affecting the price it receives for the good it produces c. the firm's profit is the same at each quantity it sells d. the firm can make no choices

Which of the following statements is (are) true? i. free entry to a perfectly competitive industry results in the industry's firms earning zero economic profit in the long run, except for the most efficient producers, who may earn economic rent. ii. in a perfectly competitive market, long-run equilibrium is characterized by lmc < p < latc. iii. if a competitive industry is in long-run equilibrium, a decrease in demand causes firms to earn negative profit because the market price will fall below average total cost.