Final answer:
The term for the number of subordinates reporting directly to a manager is the 'span of control' which defines the extent of a manager's oversight in an organizational structure.
Step-by-step explanation:
The term that refers to the number of subordinates who report directly to a manager is known as the span of control. This concept is an essential aspect of organizational structure and speaks to how managers or supervisors interact with their direct reports. A manager with a broad span of control oversees many employees, while a narrow span means they manage fewer individuals. Considering the options provided, the correct answer is D. span of control.
In contrast, esprit de corps refers to the spirit of camaraderie among members of a group, synergy is the combined effect that exceeds the sum of individual effects, economies of scale refer to the cost advantages achieved due to the scale of operation, and autonomy involves the degree of freedom and independence in decision-making.