The Parliament of India acquires the power to legislate on any item in the State List in the national interest if a resolution to that effect is passed by the

1. A

   Lok Sabha by a simple majority of its total membership

   Lok Sabha by a simple majority of its total membership is not the Article 249 procedure. The Council of States, not the House of the People, must first declare a State List matter to be of national interest. This option is not the key.

2. B

   Lok Sabha by a majority of not less than two-thirds of its total membership

   A two-thirds majority of Lok Sabha’s total membership is a different special-majority idea (and still the wrong House). Article 249 does not vest this power in Lok Sabha. This option is wrong.

3. C

   Rajya Sabha by a simple majority of its total membership

   Rajya Sabha by a simple majority of its total membership is too weak and misstates the quorum of the special majority. Article 249 requires two-thirds of members present and voting. This option is not the key.

4. D

   Rajya Sabha by a majority of not less than two-thirds of its members present and voting

   Article 249 lets Parliament legislate on a State List subject in the national interest if Rajya Sabha passes a resolution to that effect by a majority of not less than two-thirds of the members present and voting. That is the official key.

Summary. Official key is (d) Rajya Sabha by a majority of not less than two-thirds of its members present and voting. The Rajya Sabha represents States, so the Constitution gives it this exceptional gate. The resolution lasts one year at a time and can be renewed; laws may continue for a limited period after it ends. Lok Sabha majorities, simple or special, are not the trigger. Article 250 (Emergency) and Article 252 (two or more States) are different routes.