Correct answer: (a) Tripura
Explanation
- A
Tripura
(a) Tripura. The Sixth Schedule applies to Assam, Meghalaya, Tripura and Mizoram (certain tribal areas). Tripura is on that list, so it is the official key among these options.
- B
Sikkim
(b) Sikkim. Sikkim has Article 371F special provisions, not Sixth Schedule autonomous districts.
- C
Nagaland
(c) Nagaland. Nagaland is governed by Article 371A, not the Sixth Schedule.
- D
All of the above
(d) All of the above. Fails because Sikkim and Nagaland are outside the Sixth Schedule.
Summary. Official key is (a) Tripura. Sixth Schedule States are Assam, Meghalaya, Tripura, Mizoram. Nagaland is 371A; Sikkim is 371F. ‘All of the above’ is therefore wrong. Honour the stored letter (a).