Herbivores than Carnivores
The correct answer is option b, that is, herbivores than carnivores.
An ecosystem refers to a biological community of interrelating species and their physical surrounding. An ecosystem refers to a community comprising of living species and non-living constituents, like air, mineral soil, and water.
In a food chain, energy is transported from one link to another. When a herbivore consumes greenery, only some of the energy turns into the new body mass, while the rest of the energy is lost as waste or consumed by the herbivore itself to conduct its own life procedures.
Thus, a carnivore has to consume many herbivores to get the adequate energy to thrive and develop. This is the reason that in an ecosystem, there are more herbivores than carnivores.