Which of the following sequence of Statehood (in an ascending order) is correct?

Concept: A State's ‘date of statehood’ is the day it acquired full State status under the Constitution of India or an Act of Parliament — distinct from when it was a colonial province, a princely state, a Union Territory, or part of another State. To arrange several States ‘in ascending order’ of statehood, rank them strictly by that calendar date, earliest first — never by alphabetical name or by their numeric position (16th State, 22nd State, etc.) in the Indian Union.

Application:

1. Assam became a full State on 26 January 1950, the day the Constitution of India commenced, as one of the original States of the Indian Union (successor to colonial Assam Province).

2. Nagaland was carved out of Assam and became India's 16th State on 1 December 1963, under the State of Nagaland Act, 1962.

3. Tripura was elevated from a Union Territory to a full State on 21 January 1972, under the North-Eastern Areas (Reorganisation) Act, 1971 (the same Act created Meghalaya and Manipur as States on the same day).

4. Sikkim became India's 22nd State on 16 May 1975, under the Constitution (Thirty-sixth Amendment) Act, 1975, following the 1975 referendum that abolished the monarchy.

Cross-check: Checking each offered sequence against these dates:

• Sikkim – Tripura – Assam – Nagaland places the two most recently formed States (Sikkim, 1975, and Tripura, 1972) ahead of Assam (1950), so it runs opposite to the actual chronology at the start.

• Assam – Tripura – Nagaland – Sikkim gets the first and last positions right but swaps the middle pair — Nagaland (1963) attained statehood before Tripura (1972), not after.

• Assam – Sikkim – Tripura – Nagaland gets Assam right at the start but inserts Sikkim (1975), the last State of the four to form, in second place — well ahead of Tripura and Nagaland.

Answer: Only Assam – Nagaland – Tripura – Sikkim reproduces the true ascending chronology: 1950 → 1963 → 1972 → 1975.