The correct option is A 4 chambered
Bat belongs to group Mammalia as they have body hair, they are warm-blooded and nurse their babies with milk. Mammals possess 4 chambered heart (two auricles and two ventricles). To maintain the body temperature in mammals, 4 chambered heart is needed, as it prevents the complete mixing of deoxygenated and oxygenated blood. Hence, the correct answer is option A.