A company must meet the following demands on time: month 1, 1 unit; month 2, 1 unit; month 3, 2 units; month 4, 2 units. It costs $4 to place an order, and a $2 per-unit holding cost is assessed against each month’s ending inventory. At the beginning of month 1, 1 unit is available. Orders are delivered instantaneously. Use dynamic programming to determine an optimal ordering policy.