Correct Option (B)
An ecological niche describes the total sum of an organism's interactions with its environment. This includes not only the physical space it occupies (its habitat) but also its functional role within the community of organisms. The functional role encompasses aspects such as its position in the food web, the resources it utilizes, its reproductive strategies, and its interactions with other species (both biotic and abiotic components). It essentially defines how an organism 'makes a living' and maintains its population within an ecosystem.
Incorrect Options
Ecotone:
An ecotone is a transitional zone or boundary area between two distinct ecosystems. For example, the area between a forest and a grassland, or between a freshwater and a marine environment. It often exhibits characteristics of both adjacent ecosystems and may contain a unique mix of species. It does not describe the functional role of a specific organism.
Habitat:
A habitat refers to the specific physical environment or place where an organism or a population naturally lives. It provides the necessary resources for an organism's survival, such as food, water, and shelter. While essential, habitat only defines the 'address' or living space of an organism, not its 'profession' or functional role within the community.
Home range:
A home range is the area over which an animal or group of animals regularly travels in search of food, water, or mates, and where it spends most of its time. Unlike a territory, a home range is typically not actively defended against conspecifics. It describes the spatial extent of an animal's daily or seasonal activities but does not encompass its broader functional role in the ecosystem.