In the popular block letter format, which of the following guidelines apply? a. Double-space all content to improve readability. b. Use fully justified margins on all sides and center the body of the letter on the page. c. Use ragged, unjustified right margins. d. Start the sender's address, the dateline, and the complimentary close at the midpoint; align all other letter parts at the left margin.

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.