The Economic Order Quantity (EOQ) model is designed to determine the optimal order quantity that minimizes the total costs of inventory, including ordering and holding costs. A key assumption of the EOQ model is that the rate of demand is continuous and constant. This means that the demand for the product does not fluctuate significantly over time, allowing for a steady and predictable rate of consumption. This assumption simplifies the calculation by ensuring that order cycles are regular and inventory depletion occurs at a consistent rate. Options A, C, and D do not align with the fundamental assumptions of the EOQ model.