Answer:
The correct answer would be B. predator and prey.
Predator and prey is a type of natural relationship in which one organism kills and consume the other organism.
For example, a lion is a predator which kills and consume deer (prey).
During the course of evolution, prey evolves various adaptations to overcome predation and increases its survival rate.
In addition, a predator also evolves to increase its success rate in predation.
Similarly, rough-skinned newts (prey) evolve to produce poison as a defense mechanism and greater snakes (predator) evolve resistance against that poison to increase its survival rates.