Homoiothermal animals, also known as warm-blooded animals, are those that can regulate their body temperature internally. This means that regardless of the external temperature, their body temperature remains relatively constant.

The correct answer is option B, which includes Bat, Pigeon, and Rabbit as homoiothermal animals. Let's take a closer look at each of these animals:

1. Bat: Bats are mammals that are capable of maintaining a constant body temperature, even when they are flying in cold temperatures. They do this by increasing their metabolic rate and generating heat internally.

2. Pigeon: Pigeons are also homoiothermal animals, capable of regulating their body temperature internally. They do this by fluffing up their feathers to trap warm air close to their bodies, and by increasing their metabolic rate when it is cold outside.

3. Rabbit: Rabbits are another example of warm-blooded animals. They have a high metabolic rate and can generate heat internally to maintain a constant body temperature.

On the other hand, option A includes Frog, Lion, and Fish, which are not homoiothermal animals. Frogs and fish are cold-blooded animals, meaning that their body temperature is determined by the external environment. Lions, on the other hand, are homoiothermic animals, meaning that their body temperature remains relatively constant, but they are not considered warm-blooded animals as they do not regulate their body temperature internally.

Option C includes Pigeon, Lizard, and Tortoise. While pigeons are homoiothermal animals, lizards and tortoises are not. Lizards are cold-blooded animals, and tortoises are ectothermic animals that rely on external sources of heat to regulate their body temperature.

Option D includes Rat, Snake, and Crocodile. While rats and snakes are homoiothermal animals, crocodiles are not. Crocodiles are ectothermic animals that rely on external sources of heat to regulate their body temperature.

The animals which belongs to class aves and mammalia are homoiothermal because they can maintain a constant internal condition in their body irrespective of the changing environmental conditions therefore correct option is B