a business owner makes 1,000 items a day. each day she contributes eight hours to produce those items. if hired, elsewhere she could have earned $250 an hour. the item sells for $15 each. production does not stop during weekends. if the explicit costs total $150,000 for 30 days, the firm's accounting profit for the month equals a. $300,000. b. $60,000. c. $450,000. d. $240,000.