Barak The Barak River is important in Manipur and Mizoram, but it does not flow through Arunachal Pradesh.

Lohit The Lohit River originates in the eastern end of the Himalayas in the Mishmi Hills of Arunachal Pradesh and flows through the districts of Anjaw, Lohit, and Dibrugarh in Arunachal Pradesh.

Subansiri The Subansiri River is a tributary of the Brahmaputra River and flows through Arunachal Pradesh.

Therefore, only the Lohit and Subansiri rivers flow through Arunachal Pradesh.

Option (b) 2 and 3 only