A predator "preys" on other animals for sustenance.
X A) decomposer because, as the name says, these organisms simply decompose dead things.
X B) producer because these organisms produce their own food instead of preying on others.
X C) herbivore because these organisms eat only vegetables and the like.
So the answer is D) carnivore because carni-vores eat meat (or carni- from the root) gained by hunting another animal.