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Question 3. A store starts a week with at least 3 PCs. The demand per week is estimated at 0 with probability 0.15, 1 with probability 0.2, 2 with probability 0.35, 3 with probability 0.25, and 4 with probability 0.05. Unfilled demand is backlogged. The store's policy is to place an order for delivery at the start of the following week whenever the inventory level drops below 3 PCs. The new replenishment always brings the stock back to 5 PCs. a. Express the situation as a Markov chain. b. Suppose that the week starts with 4 PCs. Determine the probability that an order will be placed at the end of two weeks. 0. Determine the long-run probability that no order will be placed in any week. d. If the fixed cost of placing an order is $200, the holding cost per PC per week is $5, and the penalty cost per shortage PC per week is $20, determine the expected inventory cost per week