Explanation:

Recently, Arunachal Pradesh Chief Minister and his Assam counterpart have decided to form district-level committees for settling their inter-state boundary disputes.

• The issue started with a 1951 report which transferred 3,648 sq. km of the “plain” area of Balipara and Sadiya foothills to the Darrang and Lakhimpur districts of Assam.
• Arunachal Pradesh claims the transfer was done without consulting its tribes who had customary rights over these lands.
• The two States have decided to form 12 committees involving the districts sharing the boundary in order to come up with a solution.
• Assam has had boundary disputes with all the north-eastern States that were carved out of it.
• While Nagaland became a State in 1963, Meghalaya first became an Autonomous State in 1970 and a full-fledged State in 1972.
• Arunachal Pradesh and Mizoram were separated from Assam as Union Territories in 1972 and as States in 1987.

Hence only statement 1 is correct.