The correct answer is C. reorder level.
The reorder level is the point at which the store keeper should initiate purchase requisition for fresh supply. It is the level of inventory at which a new order should be placed to ensure that there is always enough stock on hand to meet demand.
The minimum stock level is the lowest level of inventory that should be maintained. If the stock level falls below this level, the store may not be able to meet demand and may lose sales.
The maximum stock level is the highest level of inventory that should be maintained. If the stock level exceeds this level, the store may incur unnecessary costs, such as storage costs and obsolescence costs.
The average stock level is the average of the maximum and minimum stock levels. It is not a useful measure for determining when to place a new order.