The correct answer is option 'b' - Indira Nehru Gandhi v. Raj Narain case (1975).

Explanation:
The case of Indira Nehru Gandhi v. Raj Narain in 1975 was a significant judicial decision that struck down Clause (4) of Article 329-A, which was inserted by the 39th Amendment in 1975. This case was related to the election of Indira Gandhi, the then Prime Minister of India, and it had far-reaching implications on the constitutional amending power of the Parliament.

Background:
In 1971, Raj Narain, an opposition candidate, filed a petition challenging the election of Indira Gandhi from the Rae Bareli constituency. The Allahabad High Court found Indira Gandhi guilty of electoral malpractices and declared her election void. As a result, she was disqualified from holding any public office for six years. However, during the pendency of the appeal in the Supreme Court, the Parliament passed the 39th Amendment, which introduced Article 329-A to protect the election of the Prime Minister, President, and Speaker of the Lok Sabha from judicial scrutiny.

Key Arguments:
- Raj Narain argued that the 39th Amendment was unconstitutional as it violated the basic structure of the Constitution, which includes the principles of democracy and free and fair elections.
- The main contention was whether the Parliament had the power to amend the Constitution in a manner that destroyed its basic features, as laid down in the landmark case of Kesavananda Bharati (1973).

Supreme Court's Decision:
The Supreme Court, in its judgment, held that the Parliament's power to amend the Constitution under Article 368 was not unlimited and that it could not alter or destroy the Constitution's basic structure. The court ruled that Clause (4) of Article 329-A, which sought to exclude election disputes of the Prime Minister, President, and Speaker from judicial review, was unconstitutional as it violated the basic structure doctrine.

Significance of the Case:
The case of Indira Nehru Gandhi v. Raj Narain was a significant milestone in the development of the basic structure doctrine. It established that the Parliament's amending power was not absolute and could not be used to destroy the core principles of the Constitution. This case reaffirmed the supremacy of the Constitution and the power of the judiciary to strike down any constitutional amendment that violates the basic structure.

Overall, the case of Indira Nehru Gandhi v. Raj Narain played a crucial role in upholding the sanctity of the Constitution and protecting its basic features from being tampered with by the Parliament.