The correct option is D Biotic community
Individuals of the same species that live in a geographic area at a particular time is called a population.
An assemblage of populations of two or more different species occupying the same geographical area and having functional interactions is called a biotic community.
Interaction of biotic communities with the physical environment forms an ecosystem.
The organism has a defined range of conditions that it can tolerate, diversity in the resources it utilises and a distinct functional role in the ecological system, all of which together comprise its niche.
So, the correct answer is option C.