Correct Answer: 4) Indus

Detailed Explanation:

This question tests your knowledge of Indian Geography, specifically the major river systems. Let's break down the logic to arrive at the correct answer.

1. Identify the Geographical Location: The first step is to recognize where the Nubra and Shyok rivers are located. Both rivers flow through the Ladakh region, which is in the northernmost part of India.
2. Identify the Major River in the Region: The principal river that flows through the Ladakh region is the Indus River. It is one of the longest rivers in Asia and has a vast network of tributaries in this area.
3. Trace the River Flow and Relationship:
   • The Nubra River originates from the Siachen Glacier.
   • It flows south to join the Shyok River. Thus, the Nubra is a tributary of the Shyok.
   • The Shyok River itself originates from the Rimo Glacier and flows for a considerable distance before merging with the Indus River near Skardu.
   • Since the Nubra flows into the Shyok, and the Shyok flows into the Indus, both are considered tributaries of the Indus River.
4. Evaluate and Eliminate Other Options:
   • 1) Sutlej: While the Sutlej is also a part of the Indus river system, it flows to the south of Ladakh, primarily through Himachal Pradesh and Punjab. The Nubra and Shyok rivers are not its tributaries.
   • 2) Narmada: The Narmada is a major west-flowing river in Peninsular India, originating in Madhya Pradesh. It is geographically very distant from Ladakh and the Himalayan river systems.
   • 3) Kaveri: The Kaveri is a major river of South India, flowing through Karnataka and Tamil Nadu. It has no connection to the Himalayan rivers.

Based on this geographical analysis, the Nubra and the Shyok are unequivocally tributaries of the Indus River.