The correct option is The Subansiri.
Explanation
The Brahmaputra river system consists of numerous tributaries that join it on both the right and left banks. An antecedent river is one that existed before the upliftment of the Himalayas and maintained its course by cutting through the rising mountain ranges, forming deep gorges. Several major Himalayan rivers, including the Indus, Sutlej, Brahmaputra, and Subansiri, are antecedent in nature.
Detailed Analysis:
- The Subansiri (Correct): It originates in the Himalayas in Tibet. It is an antecedent river that cuts through the Himalayas to enter India in Arunachal Pradesh. It is the largest tributary of the Brahmaputra and joins it on the right bank in Assam.
- The Lohit: It originates in Tibet (Zayal Chu) but joins the Brahmaputra on the left bank.
- The Dhansari: It originates from Laisang peak in Nagaland (south of the Brahmaputra) and joins the river on its left bank.
- The Dibang: It originates near the Indo-Chinese border in Arunachal Pradesh and joins the Brahmaputra (Siang) on the left bank.
Key Takeaway:
The Subansiri is a major right-bank tributary of the Brahmaputra that originates in Tibet and exhibits antecedent drainage characteristics.