A popular ecotourism destination in Nagaland, known for its scenic beauty and trekking trails, is:

Dzukou Valley
Kohima
Mokokchung
Dimapur

The correct answer is: a) Dzukou Valley.

Dzukou Valley is a high-altitude valley located in the Naga Hills of Nagaland, India. It is a popular ecotourism destination, known for its scenic beauty and trekking trails. The valley is home to a variety of plant and animal life, including the endangered Dzukou Lily. The valley is also a popular destination for birdwatching.

Kohima is the capital of Nagaland. It is a city with a rich history and culture. The city is home to a number of historical sites, including the Kohima War Cemetery and the Naga Heritage Village. Kohima is also a popular destination for shopping and dining.

Mokokchung is a town in Nagaland. It is the second largest town in the state after Kohima. Mokokchung is known for its traditional Naga culture and handicrafts. The town is also home to a number of educational institutions, including the Nagaland University.

Dimapur is the largest city in Nagaland. It is a commercial and industrial hub of the state. Dimapur is also a popular destination for shopping and dining. The city is home to a number of hotels and restaurants.