The correct option is C Interbreeding
A species is a group of organisms which can interbreed successfully to produce fertile offspring. Thus, they are not reproductively isolated, irrespective of their habitat. Niche is the ecological role of an organism in the ecosystem. No two individuals share the same niche. If they did, they would be competing for every single resource, and the individual better suited to that niche could apparently drive the other to death. Every organism fits into the environment in its own special way, with different needs, interactions, and tolerance ranges to different conditions.