Opportunity cost represents the return a firm forgoes by investing resources in one use instead of the next best alternative. In inventory management, capital tied up in inventory cannot be used for other value-generating activities such as investing in new projects, paying down debt, or returning cash to shareholders. Financial management emphasizes opportunity cost as a key component of inventory carrying costs, along with storage, insurance, and obsolescence. Ignoring opportunity costs can lead to excessive inventory levels and reduced firm value. Option B correctly identifies this fundamental concept.