Final answer:
The correct term for a unit operating by its own rules and not sharing information is a 'silo'. Coercion to join is not a characteristic of bureaucracies which generally have a structured hierarchy, clear rules, and a division of labor.
Step-by-step explanation:
The term that refers to a functional or divisional unit that operates by its own rules and guidelines and does not openly share information with other units is known as a silo. In a business context, silos can lead to inefficiencies as they prevent the sharing of information and resources, which can hinder overall performance. Therefore, the correct answer from the provided options is b. Silo.
Regarding the characteristics of bureaucracies, answer a. Coercion to join is not typically considered a characteristic of a bureaucracy, while a hierarchy of authority, explicit rules, and a division of labor are indeed standard characteristics. Bureaucracies are known for having structured hierarchies and well-defined roles, often to ensure efficiency and predictability in an organization's operations.