The weekly demand for a product is 770 units. The standard deviation of daily demand is 10 units. The firm reviews its inventory every 28 days. Each order for the product arrives 9 days after placement. At the time of review, there are 10 units on backorder. If 95 percent of all demand is to be satisfied from items in stock: a) How many units should be the safety stock? b) What's the product's inventory status? c) How many units should be ordered for this period