The correct answer is: Hilly regions.
The Naga tribes in Manipur are primarily found in the hilly regions of the state. The hilly regions of Manipur are home to a diverse range of ethnic groups, including the Nagas. The Nagas are a group of indigenous peoples who live in the northeastern states of India and the northern states of Myanmar. The Nagas are known for their unique culture and traditions.
The Imphal Valley is a lowland region in the center of Manipur. The Imphal Valley is home to the majority of the population of Manipur. The Imphal Valley is a major economic and cultural center of Manipur.
The southern districts of Manipur are also home to a number of Naga tribes. However, the Naga tribes in the southern districts are not as numerous as the Naga tribes in the hilly regions.
The coastal areas of Manipur are home to a number of different ethnic groups, including the Meiteis, the Kukis, and the Chins. The Naga tribes are not found in the coastal areas of Manipur.