If the Prime Minister of India belonged to the Upper House of Parliament

The Prime Minister, if belonging to the Rajya Sabha, cannot vote in Lok Sabha proceedings because ministers who are not members of a particular House may participate in its proceedings but are not entitled to vote there [1]. A no-confidence motion is a Lok Sabha mechanism — the Lok Sabha alone controls the Council of Ministers and can express no confidence; the Rajya Sabha does not exercise this power [2]. Therefore a PM from the Upper House cannot cast a vote in the Lok Sabha on a no-confidence motion. Options 2 and 3 are incorrect because ministers may speak in either House [1]. Option 4 is incorrect as there is no rule requiring a PM who is already a Rajya Sabha member to become a Lok Sabha member within six months.

Sources

1. [1] Indian Polity, M. Laxmikanth(7th ed.) > Chapter 23: Parliament > Rights of Ministers and Attorney General > p. 239
2. [2] Democratic Politics-I. Political Science-Class IX . NCERT(Revised ed 2025) > Chapter 4: WORKING OF INSTITUTIONS > Two Houses of Parliament > p. 63