The data dictionary serves as .a. an important data management tool by assigning attributes to the data. b. creating an inventory of the data elements contained in the database. c. presenting data as end users or business specialists would perceive them. d. maintaining data in updated form.

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.