Consider the following rivers: (1). Barak (2). Lohit (3). Subansiri Which of the above flows / flow through Arunachal Pradesh?

The correct answer is B (2 and 3 only). Lohit and Subansiri both flow through Arunachal Pradesh, while Barak does not.

• Lohit (2) is correct. It is a major tributary of the Brahmaputra, rising in the eastern Himalayas and flowing through Arunachal Pradesh. Parasuram Kund, in Lohit district, lies on its course.
• Subansiri (3) is correct. It rises in Tibet, enters India through Arunachal Pradesh, and then forms part of the Arunachal-Assam boundary before joining the Brahmaputra in Assam.
• Barak (1) is wrong. It rises in the Manipur hills (Barail range), flows through Assam's Barak Valley, and enters Bangladesh as the Surma-Meghna system. It never enters Arunachal.

The core concept is the drainage pattern of the Brahmaputra system versus the Barak system, a standard Physical Geography topic. For Mains, the Subansiri and Lohit basins matter for hydropower projects and for Assam's concerns over upstream dams and flow regulation.

Trap: many aspirants pick A or C because Barak is a familiar name from Northeast geography and they assume it touches every northeastern state. Check each river's origin and course instead of relying on the state name.