The correct answer is: a) Great Hornbill.
The Great Hornbill is a large, colorful bird with a long, curved beak. It is found in the forests of Southeast Asia, including Arunachal Pradesh. The Great Hornbill is a monogamous bird, and pairs mate for life. They build their nests in tall trees, and the female lays one or two eggs. The chicks are altricial, meaning that they are born helpless and require care from their parents. The Great Hornbill is an important part of the ecosystem, and its presence indicates a healthy forest. It is also a popular tourist attraction, and many people come to Arunachal Pradesh to see these amazing birds.
The other options are incorrect. The Peacock is the national bird of India, but it is not the state bird of Arunachal Pradesh. The Kingfisher is a small, colorful bird that is found in many parts of the world, including Arunachal Pradesh. The Hoopoe is a medium-sized bird with a long, curved beak. It is found in Europe, Asia, and Africa.
The Great Hornbill is a beautiful and majestic bird that is an important part of the ecosystem. It is also a popular tourist attraction, and many people come to Arunachal Pradesh to see these amazing birds.