Joe's Coffee Shoppe has fresh doughnuts delivered each morning. Daily demand for plain doughnuts is approximately normal with a mean of 200 and a standard deviation of 30. Joe pays $0.20 per doughnut and sells it for $0.55. At the end of the day, 2/3 of the unsold doughnuts are sold at 0.25 each, and Joe and the staff eat any leftovers. Which of the following ranges includes the optimal order size?