Which Army publication outlines the overarching principles of sustainment?

The correct choice is ADP 4-0 Sustainment because it specifically focuses on the principles and approaches related to sustainment within the Army. This publication serves as a foundational document that outlines how the Army will support its operations through various means such as personnel, logistics, and health services. It emphasizes the importance of sustainment to ensure operational readiness and effectiveness, and it articulates the policies, roles, and responsibilities associated with sustainment operations.

In contrast, the other options address different aspects of Army operations. For instance, ADP 1-0 Operations provides a general overview of Army operations as a whole, covering a broad spectrum of tactics and strategies without delving into the specifics of sustainment. ADP 5-0 Planning focuses on the planning processes used within the Army, including the operational planning process but not specifically on sustainment principles. Similarly, ADP 6-0 Mission Command centers around the command and control practices essential for effective Army leadership and is not solely concerned with the principles of sustainment. Thus, ADP 4-0 is the key publication for understanding how sustainment underpins overall Army functionality.