The correct answer is A. Nullah.
A nullah is a small stream or channel of water, especially one that is dry except in the rainy season. It is not a tributary of the Indus River.
The Indus River is the longest river in Pakistan and the second-longest river in India. It is also the largest river in the Indian subcontinent. The Indus River originates in the Tibetan Plateau and flows through Ladakh, Jammu and Kashmir, Himachal Pradesh, Punjab, Haryana, Rajasthan, and Sindh. The Indus River is a major source of irrigation water for agriculture in Pakistan and India.
The tributaries of the Indus River include the Jhelum, Chenab, Ravi, Sutlej, Beas, and Ghaggar-Hakra rivers. The Jhelum River is the largest tributary of the Indus River. It originates in the Pir Panjal Range in the Indian state of Jammu and Kashmir. The Chenab River is the second-largest tributary of the Indus River. It originates in the Dhauladhar Range in the Indian state of Himachal Pradesh. The Ravi River is the third-largest tributary of the Indus River. It originates in the Pir Panjal Range in the Indian state of Jammu and Kashmir. The Sutlej River is the fourth-largest tributary of the Indus River. It originates in the Himalayas in the Indian state of Himachal Pradesh. The Beas River is the fifth-largest tributary of the Indus River. It originates in the Himalayas in the Indian state of Himachal Pradesh. The Ghaggar-Hakra River is the sixth-largest tributary of the Indus River. It originates in the Himalayas in the Indian state of Himachal Pradesh.
The Indus River is a major source of water for irrigation and drinking water in Pakistan and India. The Indus River is also a major source of hydroelectric power. The Indus River is a vital part of the economy of Pakistan and India.