With reference to the Indus river system, of the following four rivers, three of them pour into one of them which joins the Indus direct. Among the following, which one is such river that joins the Indus direct?
Explanation
The Sutlej is the river that joins the Indus directly after receiving the collective drainage of the other three rivers. According to NCERT Class 11 (India: Physical Environment), the Jhelum and Ravi rivers join the Chenab, and the Chenab subsequently joins the Sutlej in Pakistan. The Sutlej then flows into the Indus a few kilometres above Mithankot. Thus, the Sutlej acts as the final conduit for the combined waters of the Jhelum, Ravi, and Chenab before their confluence with the Indus. This geographical sequence is confirmed by the official UPSC Answer Key for the 2021 Prelims, which identifies Option D as the correct answer.