4. Consider a single product inventory problem with stochastic demand sold by a small retail store. The store owner's daughter, Jess, is studying industrial engineering and has estimated the following. the fixed ordering cost A = $100/order the inventory carrying cost rate i = $0.2/$ inventory/yr the unit cost C = $5/unit the backorder cost a = $10/unit backordered the order lead-time t= 1 month lead time demand is Normally distributed with an average rate D=1000 units/month and standard deviation o=200 units/month. a. Using the standard EOQ model, what would the retailers lot size be? Given this lot size, on average, how many orders would be made per year? b. Given the lot size computed in part a. what should the reorder point be to minimize cost? For the reorder point computed in part b., what should the lot size be now? d. The owner of the retail store is not comfortable with Jess's estimate of the backorder cost. Instead, the owner prefers to make, on average, quarterly orders on the supplier and to try to meet a target service level during an order cycle of 0.9. Given this, what lot size and reorder point should be used? c