Which of the following statements is NOT true about a fixed-period system? a. A fixed-period system is also called "continuous review". b. The disadvantage of the fixed-period system is that because there is no tally of inventory during the review period, there is the possibility of a stockout during this time. c. The advantage of the fixed-period system is that there is no physical count of inventory items after an item is withdrawn. d. A fixed-period system is appropriate when vendors make routine visits to customers to take fresh orders or when purchasers want purchasers want to combine orders to save ordering and transportation costs.