Suppose a firm sells a good for a perfectly competitive price of $5. The equilibrium wage rate is $10. The first worker it hires produces five units. Two workers produce a total of nine units. If it hires two workers, the value of marginal product for the second worker is .

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.