The correct answer is: a) Patkai Range.
The Patkai Range is a mountain range in the eastern Himalayas that forms a natural boundary between Arunachal Pradesh and Myanmar. It is a sub-range of the Eastern Himalayas and runs for about 500 kilometers from the Brahmaputra River in India to the Chindwin River in Myanmar. The highest peak in the Patkai Range is Mount Patkai, which is 3,097 meters (10,165 feet) tall.
The Patkai Range is a major watershed, with the rivers on its eastern side flowing into the Chindwin River and the rivers on its western side flowing into the Brahmaputra River. The range is also a major biodiversity hotspot, with a wide variety of plant and animal life.
The Patkai Range is a popular destination for trekking, hiking, and camping. The best time to visit the range is during the winter months, when the weather is cooler and drier.
The other options are incorrect because:
- The Karakoram Range is a mountain range in Central Asia that forms a natural boundary between Pakistan and China.
- The Mishmi Hills are a mountain range in northeastern India that forms a natural boundary between Arunachal Pradesh and Assam.
- The Himalayas are the highest mountain range in the world and form a natural boundary between India, Nepal, Bhutan, China, and Pakistan.