A cardiac department within a local hospital carries out a small number of specialist emergency care heart surgeries each year. The devices implanted in the patients can vary significantly depending on the condition of the patient. Therefore, the hospital requires a stock management technique that minimizes the cost of holding several different items of stock, without impacting the critical service levels, and allowing the supplier to retain the title of the stock until the hospital’s cardiac team utilizes it. Which of the following stock management techniques would enable the hospital to achieve this?