Tochi, Gilgit and Hunza are important tributaries of which of the following major rivers of the Indian subcontinent?

Introduction / Context:
This question belongs to the topic of major river systems in South Asia. Tochi, Gilgit and Hunza are all rivers that may not be as familiar as the Ganga or Yamuna but are significant tributaries of one of the great transboundary rivers of the region. Recognising which main river they feed into is an important part of advanced river geography for competitive exams.

Given Data / Assumptions:
- The tributaries mentioned are Tochi, Gilgit and Hunza.
- The options include the main rivers Ganga, Indus, Brahmaputra, Yamuna and Godavari.
- We are asked to identify which major river system these tributaries belong to.
- We assume standard physical geography mapping of river basins.

Concept / Approach:
The Indus River drains a large part of the northwestern Himalayas and adjoining regions. Several tributaries like Jhelum, Chenab, Ravi, Beas and Sutlej are well known within India. Further upstream and in adjoining territories, rivers such as Gilgit and Hunza join the Indus, and the Tochi River is also part of the broader Indus basin. Thus, all three names given in the question are associated with the Indus system, not with the Ganga, Brahmaputra, Yamuna or Godavari basins.

Step-by-Step Solution:
Step 1: Recall that Gilgit River flows through the region historically known as Gilgit and joins the Indus River.Step 2: The Hunza River also flows in high-altitude areas and is a tributary that merges with the Gilgit or directly with the Indus in the upper basin.Step 3: The Tochi River, sometimes referred to in western frontier geography, drains into the Kurram or directly into the Indus system, reinforcing its association with the Indus basin.Step 4: None of these rivers are mapped as tributaries of the Ganga, Brahmaputra, Yamuna or Godavari in standard atlases.Step 5: Therefore, the common major river into which Tochi, Gilgit and Hunza ultimately drain is the Indus.

Verification / Alternative check:
Looking at detailed maps of the Indus basin, particularly atlases that show the upper Indus and its smaller tributaries, you will find the Gilgit and Hunza rivers highlighted as important northern tributaries. Frontier region maps also show the Tochi flowing towards the Indus system. None of these rivers appear under the Ganga, Brahmaputra, Yamuna or Godavari basin diagrams, confirming that Indus is the correct answer.

Why Other Options Are Wrong:
Ganga: Its tributaries include Yamuna, Ghaghra, Gandak, Kosi and others, but not Tochi, Gilgit or Hunza.

Brahmaputra: Has tributaries like Subansiri, Manas and Dibang, mainly in the eastern Himalayas, not the northwestern region where Gilgit and Hunza flow.
Yamuna: A major tributary of the Ganga itself, with its own tributaries such as Chambal and Betwa, but not the rivers listed here.
Godavari: A peninsular river in central and southern India with no connection to high-altitude rivers like Gilgit and Hunza.

Common Pitfalls:
Students sometimes confuse lesser-known northern rivers with either the Ganga or Brahmaputra systems, assuming all Himalayan tributaries feed these two. The key is to remember that the Indus basin covers the northwestern Himalayan and Karakoram region, so names like Gilgit and Hunza should immediately suggest a connection to the Indus rather than to Ganga or Brahmaputra. Regular practice with basin maps greatly reduces such confusion.

Final Answer:
Indus