Correct Option (b):
The Nagavali and Vamsadhara rivers originate in the Eastern Ghats.
- The Nagavali River rises from the Eastern Ghats in the Kalahandi district of Odisha.
- The Vamsadhara River originates in the Eastern Ghats, specifically in the Gajapati district of Odisha.
Both are significant east-flowing rivers that drain into the Bay of Bengal, characteristic of the Eastern Ghats physiography.
Incorrect Options:
- Brahmani River: This river is formed by the confluence of the Sankh and South Koel rivers. Both the Sankh and South Koel rivers originate in the Chotanagpur Plateau, not the Eastern Ghats.
- Subarnarekha River: The Subarnarekha River originates in the Chotanagpur Plateau, located in Jharkhand. It does not rise from the Eastern Ghats.