The beliefs and assumptions about people, work, and the organization best reflects the

informal organization

Explanation:

Informal organization: The term informal organization refers to the social structure of a particular organization that is indifferent to the formal structure related to an organization. It aims at explaining the way an organization functions or works based on the practical aspect.

An informal organization tends to exist in a particular formal organization and describes the network of social and personal relationships and therefore it doesn't hold any rules and regulations.

In the question above, the given statement represents the informal organization.