Subansiri, Jia Bharali, Dhansiri and Puthimari are the major tributaries of which river?

Correct — D. All four rivers named in the stem are Assam rivers that empty into the Brahmaputra.

The Subansiri is its largest tributary and joins from the north after cutting through Arunachal Pradesh.

The Jia Bharali is the Kameng of Arunachal under its Assam name, and the Puthimari also comes down the north bank, while the Dhansiri rises in Nagaland and joins from the south.

The pattern itself is the clue: one valley collecting very large tributaries from both banks is the Brahmaputra in Assam.

Why the others are wrong

• (a)
  Mahanadi — The Mahanadi rises in Chhattisgarh and reaches the sea in Odisha. Its tributaries are rivers like the Seonath, the Hasdeo and the Tel, none of them in Assam.
• (b)
  Godavari — The Godavari is a peninsular river rising near Nashik, fed by the Wainganga, the Indravati, the Pranhita and the Manjra — all of them far south of the Himalaya.
• (c)
  Bhagirathi — The Bhagirathi is a Ganga headstream from the Gangotri glacier, and the same name is used for the Ganga's distributary in West Bengal. Neither channel is anywhere near the Assam valley.

The Brahmaputra changes name three times before it leaves the subcontinent.

It rises in Tibet as the Yarlung Tsangpo, swings round the Namcha Barwa massif, enters Arunachal Pradesh as the Siang or Dihang, and becomes the Brahmaputra once the Dibang and the Lohit join it in Assam.

In Bangladesh it is the Jamuna, and after it meets the Ganga the combined river is the Padma.

Because it runs the length of a narrow, very wet valley, it collects unusually large tributaries from both banks — which is why a list of unfamiliar Assam river names points to it.

Key facts

• The Subansiri is the largest tributary of the Brahmaputra and joins it from the north bank.
• The Jia Bharali is the Assam name of the Kameng river of Arunachal Pradesh.
• The Brahmaputra is called the Yarlung Tsangpo in Tibet, the Siang or Dihang in Arunachal Pradesh and the Jamuna in Bangladesh.
• The Dhansiri rises in Nagaland and joins the Brahmaputra from the south bank.

Common traps

• Counting Jia Bharali and Kameng as two different rivers.
• Choosing Bhagirathi because it sounds Himalayan, when it belongs to the Ganga system.

No directly related past PYQ was found.