The correct answer is: A. Indus
The Indus River is the longest river in Pakistan and the second-longest river in India, after the Ganges. It is also the longest river in Asia, after the Yangtze. The Indus River is a trans-boundary river, flowing through India, Pakistan, and China. The river originates in the Tibetan Plateau in the Ladakh region of India, and flows through the Ladakh and Gilgit-Baltistan regions of Pakistan before entering India again in the Punjab region. The Indus River then flows through the Indian states of Punjab, Haryana, Rajasthan, and Gujarat, before entering Pakistan again in the Sindh region. The Indus River finally discharges into the Arabian Sea near Karachi, Pakistan.
The Indus River is a major source of water for irrigation and drinking water in Pakistan and India. The river is also a major source of hydroelectric power. The Indus River is a vital part of the economies of Pakistan and India.
The Indus River is a major tourist destination. The river is home to a variety of wildlife, including fish, birds, and mammals. The Indus River is also home to a number of historical and cultural sites.
The Indus River is a beautiful and important river. It is a vital part of the lives of millions of people in Pakistan and India. The Indus River is a national treasure of Pakistan and India.
The other options are incorrect because they are not rivers that drain the Leh valley in Ladakh.
- Option B, Drass, is a town in the Leh district of Ladakh, India. It is located on the banks of the Dras River, which is a tributary of the Indus River.
- Option C, Zanskar, is a valley in the Ladakh region of India. It is located to the north of the Indus River. The Zanskar River flows through the valley.
- Option D, Shyok, is a river in the Ladakh region of India. It is a tributary of the Indus River.