The correct answer is: a) Dimapur.
Dimapur is the commercial and industrial hub of Nagaland. It is the largest city in the state and is located in the Dimapur district. The city is home to a number of industries, including textiles, food processing, and manufacturing. It is also a major transportation hub, with a railway station and an airport.
Kohima is the capital of Nagaland and is located in the Kohima district. The city is home to a number of government offices and institutions. It is also a popular tourist destination, with a number of historical and cultural sites.
Mokokchung is the third largest city in Nagaland and is located in the Mokokchung district. The city is home to a number of educational institutions and is a major center for the arts and culture.
Tuensang is the northernmost district in Nagaland and is home to a number of tribal villages. The district is known for its natural beauty and is a popular destination for trekking and adventure tourism.