Question 19 (5 points) The next three questions are based on the following information. CS System purchases computer hard drives from a supplier. CS System's weekly demand is normally distributed with a mean of 300 hard drives and a standard deviation of 75. The lead time is 6 weeks. Suppose that CS Systems uses a fixed time period model and reviews its inventory every week. If an inventory review shows that the current inventory position is 200 hard drives, the order quantity that targets a 90% service level (corresponding z = 1.28) is a) 1635 b) 2154 c) 2354 d) 1835 e) 2035 Question 20 (5 points) Suppose that CS Systems employs a fixed order quantity model. The safety stock that targets a 90% service level (corresponding z = 1.28) is _____ hard drives. a) 215 b) 1995 c) 2035 d) 235 e) 2015 Question 21 (5 points) Suppose that CS Systems employs a fixed order quantity model and it sets its safety stock level at 200 units. Which of the following statements is correct a) The company will place an order when its inventory level drops to 150 units. b) The company's service level is less than 85%. c) The company's service level is higher than 85%. d) The company's average inventory is 150 units. e) None of the above