The correct option is D Fish
∙ Two chambered heart is the characteristic feature of Pisces. All fishes are placed in Pisces.
∙ All the reptiles, except crocodiles have a three chambered heart. Crocodile is the only reptile with a four chambered heart.
∙ Pigeon comes under class Aves and possess a four chambered heart.
∙ Frog is an amphibian with three chambered heart.