Which of the following statements is correct?
A. The optimal order quantity for the quantity discount model is always at one of the price breakpoints.
B. When demand and lead time are constant, the reorder point (ROP) is less than the demand during lead time.
C. The inventory turnover ratio shows how efficiently a firm is using its inventory to generate revenue.
D. The (s, S) continuous review policy is to order the same quantity, Q, when physical inventory reaches the reorder point.