When food is derived by killing the host, this sort of interaction is

Answer: Option A

When food is derived by killing the host, this sort of interaction is Predation.
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation and parasitoidism.
Predators are adapted and often highly specialized for hunting, with acute senses such as vision, hearing, or smell.