Based on the search results, all three pairs are correctly matched: I. Arunachal Pradesh: The capital, Itanagar, is indeed named after the Ita Fort, and the state has two National Parks, Namdapha and Mouling. II. Nagaland: The state was formed based on the Constitution (Thirteenth Amendment) Act, 1962, which confirms its creation through a Constitutional Amendment. III. Tripura: Initially a Part 'C' State, it became a Union Territory in 1956 and later achieved full statehood in 1972, aligning with the historical context provided. Therefore, all three pairs are correctly matched.