Explanation:

Special Marriages Act, 1954 (SMA) 

• It is the legislation that is used to register inter-religious and inter-caste marriages in India.
• This Act includes Hindus, Muslims, Christians, Sikhs, Jains, and Buddhists marriages.
• It allows two individuals to solemnise their marriage through a civil contract. 
• There are no religious formalities that need to be carried out under the Act.
• The fundamental requirement under this Act for a valid marriage is the consent of both parties to the marriage. 
• If both parties to the marriage are willing to marry each other, that’s enough.
• No barrier: Caste, religion, race, etc. can’t act as a barrier to their union here. 

Process of marriage: 

• Prior notice: For marriage under this Act, the parties must file with the district’s Marriage Registrar a notice stating their intention to marry each other in which at least one of the parties to the marriage has lived for at least 30 days prior to the date on which such notice is filed. 
• After the expiry of 30 days from the date that such notice was published, the marriage is then said to be solemnized. 

Objections: But if any person related to the parties objects to this marriage and the registrar finds that it is a reasonable cause of objection, on such grounds he can cancel the marriage. Statement 2 is incorrect.

• For a valid marriage, the parties must also give their consent to the marriage before the marriage officer and three witnesses.

Hence option 4th is correct.