Niche/ecological niche is a specific part of habitat occupied by individuals of a species which is circumscribed by its range of tolerance, range of movement, microclimate, type of food and its availability, shelter, type of predator and timing of activity. Habitat has several ecological niches and supports a numbe of species. An ecological niche is used by a single species. Two or more species cannot use the same niche despite having a mutualistic association. Organism or populations in the competition have a niche overlap of a limited resource fo which they compete. Both owl and cat feed on shrews and mice. They occupy the same niche because of being ecological equivalents though their habitats are different.
So, the correct answer is 'Sharing of one or more resources between the two species'.