Explanation:

Chakmas and Hajongs

• Mizoram and Tripura have a sizable population of the Buddhist Chakmas while the Hindu Hajongs mostly inhabit the Garo Hills of Meghalaya and adjoining areas of Assam. 
• The Chakmas and Hajongs of Arunachal Pradesh are migrants from the Chittagong Hill Tracts of erstwhile East Pakistan, now Bangladesh. 
• Displaced by the Kaptai dam on the Karnaphuli River in the 1960s, they sought asylum in India and were settled in relief camps in the southern and south-eastern parts of Arunachal Pradesh from 1964 to 1969.
• A majority of them live in the Changlang district of the State (Arunachal Pradesh) today.

Hence only statement 2nd is correct.