Explanation:

Indira Nehru Gandhi Vs. Raj Narain

• The case of Indira Gandhi v. Raj Narain was a landmark judgment for many reasons. It was the first time in the history of independent India that a Prime Minister’s election was set aside. It was also the first time a constitutional amendment was struck down by applying the doctrine of basic structure triumphed in the Kesavanada Bharati case. It was also the first time that election laws were amended retrospectively to validate the nullified election of the Prime Minister.
• The constitutional bench gave its decision on 7th November 1975. The apex court upheld the contention of Raj Narain and declared the impugned clause 4 of Article 329A unconstitutional.
• In the words of Mathew J. Article 329A(4) destroyed the basic structure of the Constitution viz. the resolution of an election dispute by ascertaining the adjudicative facts and applying the relevant laws. He was of the opinion- “a healthy democracy can only function when there is the possibility of free and fair elections, The impugned amendment destroyed that possibility and therefore violated the basic structure of the Constitution”. Whereas Justice Khanna found that “The violation of norms of free and fair elections. The bench also found the said amendment violated the principles of natural justice 

Hence option 1st is correct.