The correct answer is (a). Arunachal Pradesh is located in the eastern Himalayas, which is a mountain range that is home to many of the world’s highest peaks. The Himalayas are a major source of water for many rivers in Asia, including the Brahmaputra, Ganges, and Indus rivers. These rivers are essential for irrigation, drinking water, and hydroelectric power generation.
The Patkai Hills are a mountain range located in northeastern India. They are not as high as the Himalayas, and they do not have as many rivers. The Deccan Plateau is a large plateau located in central India. It is a dry region, and it does not have many rivers. The Thar Desert is a desert located in northwestern India. It is the driest region in India, and it does not have any rivers.