What is one of the four primary inventory costs?

Depreciation costs represent the reduction in value of fixed assets over time, rather than costs associated with inventory management. While they are essential for financial reporting and tax purposes, they do not directly relate to the costs incurred in ordering, holding, or managing inventory.

Selling costs encompass expenses incurred in the process of selling goods, such as marketing, sales commissions, and distribution costs. While related to the overall cost structure of a business, selling costs do not represent a primary inventory cost as they focus on post-purchase activities rather than the costs of acquiring and managing inventory itself.

Sunk costs refer to expenditures that have already been incurred and cannot be recovered. They are not relevant to inventory costs since they do not influence current or future inventory decisions. Sunk costs can often lead to poor decision-making if they are considered when evaluating new inventory purchases.