A car buyer is comparing four different models of prospective used cars. Car A sold 27,000 units that year and has a reported 18,000 repair bills averaging $425 each. Car B sold 25,000 units with a reported 16,000 repairs averaging $440 each. Car C sold 30,000 units with a reported 25,000 repairs averaging $370 each. Car D sold 12,000 units with a reported 4,000 repairs averaging $510 each. Which car should this person buy if he or she wants the lowest expected repair bill?