When maintaining appropriate inventory level, a purchasing manager should ________.

A. ensure that all orders could be filled quickly, eliminating the need for back orders due to stockouts

b. implement the production plan to acquire the desired amount of finished goods available on time at a low cost

c. maintain adequate amount of inventory on hand at desired times and at a favorable price

d. keep the inventory level low, to ensure that the firm's money is not being unwisely invested in excess resources