Which One of the Following Statements About Inventory Control Systems

Which one of the following statements about inventory control systems is TRUE?

A) A two-bin inventory system is essentially a P system because the inventory is reviewed only on a periodic basis.
B) An optional replenishment system is particularly attractive when both review and ordering costs are significant.
C) Visual systems are difficult to administer because records on current inventory position have to be kept for every item.
D) Overstocking is quite common for those items that are managed by using the base-stock system.