The answer is: B. Tortoise
A centaur is a mythological creature with the head, arms, and torso of a human and the body and legs of a horse. A goat is a hoofed mammal with a beard, horns, and a short tail. A lion is a large cat with a shaggy mane and a long tail. A tortoise is a reptile with a hard shell that it can pull its head and legs into.
The tortoise is different from the other options because it is the only one that is not a mammal. The other options are all mammals, which means that they give birth to live young and nurse their young with milk. The tortoise is a reptile, which means that it lays eggs and does not nurse its young.
The tortoise is also different from the other options because it is the only one that is not a carnivore. The other options are all carnivores, which means that they eat meat. The tortoise is an herbivore, which means that it eats plants.