Choice "A" is correct. A just-in-time system is used to lower inventory levels and results in more purchase orders of fewer units each. If storage costs are increasing, JIT would be beneficial. Costs per purchase order that are decreasing would also be conducive to JIT. Changes in costs related to adoption of JIT represent a sophisticated version of an old theme in accounting: What happens to fixed costs as volume either increases or decreases? Storage costs should decrease in total; however, they will do so only as a result of ordering more frequently and maintaining fewer items in stock. Ordering more frequently will spread the costs of the purchasing department over more orders, thereby decreasing the cost per PO. Maintaining fewer items in inventory or holding items for a shorter period of time will actually increase the inventory unit carrying costs.Choices "b", "d", and "c" are incorrect based on the above explanation.