The correct answer is option 3, i.e. 1, 2 and 3 only. Joint sitting of two houses: Under the Constitution, joint sitting is an extraordinary machinery to resolve a deadlock between the two Houses over the passage of a bill. A deadlock takes place under three situations after a bill has been passed by one House and transmitted to the other House: if other house rejects the bill; if the Houses have disagreed for the amendments to be made; or if more than six months have elapsed from the date of the receipt of the bill. The president can summon both the Houses to meet in a joint sitting, in the above three situations, to deliberate and vote on the bill. Applicability of joint sitting: Applicable to ordinary bills or financial bills only and Not applicable to money bills or Constitutional amendment bills. The provision regarding the joint sitting of the two Houses has been invoked only thrice since 1950 and the bills passed are: 1st joint sitting was held in 1961 on Dowry Prohibition Bill 1960, Second in 1978 on Banking Service Commission (Repeal) Bill, 1977 and Third in 2002 on Prevention of Terrorism Bill, 2002.