The answer is A. Kiwi.
Kiwis are flightless birds native to New Zealand. They are the smallest living ratites, a group of birds that also includes ostriches, emus, and rheas. Kiwis have brown or gray feathers, a long beak, and large feet. They are nocturnal and eat insects, worms, and other small animals.
Ostriches are large, flightless birds native to Africa. They are the largest living birds, with males reaching heights of up to 9 feet and weights of up to 340 pounds. Ostriches have long, bare necks and legs, and small wings that are used for balance. They are herbivores and eat mostly plants.
Eagles are large, powerful birds of prey. They are found in all parts of the world except Antarctica. Eagles have large, hooked beaks and sharp talons. They are carnivores and eat mostly mammals, birds, and reptiles.
Penguins are flightless birds that live in the Southern Hemisphere. They are well-adapted to cold climates, with thick feathers and a layer of fat to keep them warm. Penguins are carnivores and eat mostly fish, squid, and krill.
The word that is different from the rest is kiwi. Kiwis are the only flightless bird on the list. The other three birds are all able to fly.