Smylie & Son uses a fixed-period system to manage its inventory of hand-rolled cigars. One model, the "el diablo," enjoys robust demand at 480 boxes per week (20 cigars per box) with a standard deviation of 120. Cigars must be stored in a carefully controlled climate, so storage costs are $5/cigar per year. Smylie and Son's supplier is located on an island south of Miami, Florida, and ordering is complicated and thus expensive, at $1,500 an order. Even at that price, it takes an average of six weeks to receive a shipment. El diablo is popular even at the exorbitant price Smylie & Son charges, so the company sets the replenishment level at an even 7,000. What is the service level it is using? a. 73% b. 89% c. 65% d. 81%