This is a delimited space that a person or a group of persons uses and defends as an exclusive preserve.

The term that describes a delimited space that a person or a group of persons uses and defends as an exclusive preserve is known as "Territory." This concept encompasses not only the physical aspect of space but also the sociocultural significance attached to it. In the context of human behavior and social organization, territory reflects a sense of belonging, control, and identity within a specified area.

Territory can vary significantly in scale, from personal spaces like a bedroom to larger communal areas or regions claimed by groups. The act of defending this space often relates to both physical boundaries and psychological perceptions of ownership and safety.

The other options highlight related concepts but do not capture the definition as accurately. Ownership refers more specifically to the legal or formal rights over a space, while human settlement relates to the patterns of living arrangements that people form in a given area. Defensible Space, although it pertains to aspects of security and territoriality in architecture, is defined primarily by design strategies that deter crime and promote safety, rather than simply the act of defending a space as a territory does. Thus, "Territory" is the most appropriate choice in this context.