Answer:
A. Mutualism
Explanation:
Mutualism is a type symbiotic relationship which involves an ecological interaction or association between organisms of different species in which each specie benefit from each other. Sometimes, both of the species depend on each other for survival.
In this scenario, the bird benefits (food) from the mammal by eating the insects off the mammal body while the mammal also benefits because it gets rid of blood sucking insects which are harmful to them.
