Weekly demand for walnut fudge ice cream at the Sweet Creamery can be approximated by a normal distr

Weekly demand for walnut fudge ice cream at the Sweet Creamery can be approximated by a normal distribution with a mean of 21 gallons and a standard deviation of 3.5 gallons. The lead time for procurement of walnut fudge ice cream is 1 week, and the dairy is open seven days a week. Suppose the store reviews its inventory every Monday. For a service level of 90%, how many gallons of walnut fudge ice cream should be ordered if a weekly check shows an inventory 20 gallons? A) 20 B) 25.5 C) 28 D) 42 E) 48