The correct answer is (a) Nagaland.
The Hornbill Festival is an annual cultural festival held in Nagaland, India. It is a celebration of the rich culture and heritage of the Naga people. The festival features traditional music, dance, food, and art. It is also a time for the Naga people to come together and celebrate their unity.
The festival is held over a period of nine days in the month of December. The main venue of the festival is the Naga Heritage Village, which is located in Kisama, about 10 kilometers from Kohima, the capital of Nagaland. The village is a replica of a traditional Naga village and houses a number of traditional Naga houses.
The festival also features a number of other events, such as a beauty pageant, a fashion show, and a food festival. The Hornbill Festival is a major tourist attraction and attracts visitors from all over the world.
The other options are incorrect because they are not states in India where the Hornbill Festival is held.