Which constitutional amendment is known as the anti-defection amendment?

52nd amendment

The correct answer is Option 2 - 52nd amendment
The 52nd amendment, introduced in 1985, is known as the anti-defection amendment.

If a member remains absent in the House when asked by the party leadership to remain present or votes against the instructions of the party or voluntarily leaves the membership of the party, it is deemed as defection.

Most of the members of the legislatures are elected on the ticket of some political party. What would happen if they decide to leave the party after getting elected? For many years after independence, this issue was unresolved. Finally there was an agreement among the parties that a legislator who is elected on one party’s ticket must be restricted from ‘defecting’ to another party. An amendment to the Constitution was made (52nd amendment act) in 1985. This is known as anti-defection amendment. It has also been subsequently modified by the 91st amendment. The presiding officer of the House is the authority who takes final decisions on all such cases. If it is proved that a member has ‘defected’, then such member loses the membership of the House. Besides, such a person is also disqualified from holding any political office like ministership, etc.