The National Tribal Research Institute is located in New Delhi. It is important to note that each option given represents a different city or region in India.

Bilaspur, option 1, is a city in the state of Chhattisgarh, but it is not the location of the National Tribal Research Institute.

Raipur, option 2, is the capital of Chhattisgarh. Although it is closer to Bilaspur, it is also not the correct location for the National Tribal Research Institute.

Ranchi, option 3, is the capital of Jharkhand. While there may be tribal research institutes in Ranchi, it is not the specific location of the National Tribal Research Institute.

New Delhi, option 4, is the correct answer. New Delhi is the capital of India and is the location of various national institutions, including the National Tribal Research Institute.

Therefore, the correct answer is option 4, and the National Tribal Research Institute is situated in New Delhi.