According to the PMBOK® Guide, specifically the overview of Project Cost Management, the scope of this knowledge area extends beyond the immediate costs of project activities to include the long-term cost of ownership.

Life-Cycle Costing (Choice A): Project Cost Management should consider the effect of project decisions on the subsequent cost of using, maintaining, and supporting the product, service, or result of the project. For example, limiting the number of design reviews may reduce the project ' s cost but could increase the resulting product ' s operating costs later. This perspective is known as Life-Cycle Costing.

Project Integration Management (Choice B): While Integration Management involves making choices about resource allocation and balancing competing objectives, the specific focus on the financial impact of supporting and maintaining the product is a core tenet of Cost Management.

Project Resource Management (Choice C): This focuses on the human and physical resources needed to complete the project, rather than the long-term maintenance costs of the project ' s output.

Project Scope Management (Choice D): This ensures the project includes all the work required, and only the work required, to complete the project successfully. It defines the boundaries but does not traditionally analyze the downstream maintenance costs.

By following the principles of Project Cost Management, the project manager ensures that the project remains valuable to the organization over its entire life cycle, not just during the project ' s duration.