The correct option is C regulators
Homeostasis is the mechanism by which animals are able to regulate their internal temperature to maintain a constant, stable condition. The stability attained by homeostasis is actually a state of dynamic equilibrium, in which continuous change occurs yet a relatively uniform condition prevails.
Uniformity is basically maintained by two ways, either by conforming the internal temperature to the external temperature or by regulating the internal temperature.
Regulators can also be referred to as endotherms. These can regulate their internal environment through control mechanisms irrespective of their external surroundings to maintain a suitable internal temperature which is vital for proper functioning of the body.
Conformers can also be referred to as ectotherms as they cannot regulate their own internal temperature, they depend upon the changes in their external environment.
Phenomenon of migration is seen across the animal kingdom from tiniest insects to the great blue whale. It is the natural phenomenon by which animals set out on a journey to escape harsh weather conditions in search of food and shelter.
Hibernation is a way for many animals to survive harsh weather conditions like cold, dark winter without having to forage for food or migrate to somewhere less harsh or more suitable, rather they turn down their metabolism to save energy.