In which inventory system does the order quantity remain constant from order to order?

The correct answer is fixed order quantity ordering. In this inventory system, a specific, predetermined amount of inventory is ordered each time a reorder is triggered. This allows for a consistent approach to inventory management, making it easier for businesses to forecast inventory needs and reduce the complexity associated with varying order quantities. By maintaining a constant order quantity, companies can minimize stockouts and excess inventory, leading to better cash flow management and optimized storage costs.

Other options, such as dynamic order quantity and periodic review systems, involve changes in order quantities based on varying factors like demand variability or time intervals, leading to less predictability in inventory replenishment. The continuous review system also does not guarantee a fixed quantity, as it enables real-time monitoring of inventory levels to place orders as needed, which may result in varying order sizes depending on current stock levels.