Choice "A" is correct. The economic order quantity (EOQ) method of inventory control anticipates orders at the point where carrying costs are nearest to restocking costs. The objective of EOQ is to minimize total inventory costs. The formula for EOQ is:

Choice "b" is incorrect. Just in time (JIT) inventory models were developed to reduce the lag time between inventory arrival and inventory use.
Choice "c" is incorrect. Materials requirements planning (MRP) is a method of determining inventory requirements when a given number of units is needed. The method is used to create precise schedules of which items will be needed and what times they will be needed.
Choice "d" is incorrect. Kanban inventory control prevents either oversupply or interuption of the entire manufacturing process resulting from the lack of a component.