Which classical principle establishes the hierarchical structure of the organization, commonly called the "chain of command"?

The scalar principle is the correct answer as it specifically addresses the hierarchical structure within an organization, which is often referred to as the "chain of command." This principle emphasizes that every position in an organization should have a clear superior and subordinate relationship, creating a linear flow of authority and responsibility from the top levels of management down to the lowest levels.

This framework allows for efficient communication and accountability, as it clearly designates who reports to whom. It supports the organization in maintaining order and clarity in its operations, ensuring that everyone knows their role and responsibilities within the hierarchy.

While the other principles mentioned—like the principle of unity, principle of specialization, and principle of authority—are also important concepts in organizational structure, they do not primarily focus on establishing the hierarchical chain of command. The principle of unity emphasizes that there should be one primary objective, the principle of specialization deals with dividing tasks among individuals to increase efficiency, and the principle of authority concerns the right to give orders. These contribute to organizational functionality but do not specifically establish the hierarchical relationship that the scalar principle captures.