In difficult map-based questions on Himalayan rivers, what should receive the most attention?

Correct answer: Source, tributaries, confluence and mouth

The direct answer is A: source, tributaries, confluence and mouth. A map-based river question tests the river system and its spatial route, not decorative or biological details. Solve it step by step: first locate the source in the mountains; next trace the main channel; then identify tributaries joining it; notice important confluences; finally follow the river to its mouth, where it enters another river, a lake or the sea. Option A is correct because these four features allow a student to identify a Himalayan river and distinguish it from other rivers. Option B, the taste of river water, cannot normally be read from a physical map and is not a drainage-network feature. Option C, the number of riverside trees, is not a standard map identification clue and can change locally. Option D, the colour of fish, is irrelevant to the river course and drainage pattern. A useful exam habit is to trace every river from source to mouth and learn its major tributaries and confluences. This is more reliable than trying to remember an isolated name.