Final answer:
The management principle by Henri Fayol that an employee should report to only one superior is the Unity of Command. This principle is part of a clear hierarchy of authority essential for efficient bureaucracy and management.
Step-by-step explanation:
The principle of management by Henri Fayol that specifies that an employee should report to only one superior is B. Unity of command. This principle ensures that each subordinate receives orders from only one superior, avoiding confusion and conflict. In the context of a hierarchy of authority, this means that there is a clear and distinct line of command throughout the organization, as seen in traditional bureaucratic systems where everyone follows a chain of command from top to bottom. This principle was a foundational aspect of Fayol's work to improve organizational structure and management efficiency.