The concept 'Basic Structure of the Constitution' was propounded by the Supreme Court in the case of

1. A

   Kesavananda Bharti vs State of Kerala-1973

   Kesavananda Bharti vs State of Kerala-1973. This landmark 1973 ruling established the basic structure doctrine, holding that Parliament cannot alter the fundamental framework of the Constitution. Because this case formally propounded the doctrine, this option is the correct answer.

2. B

   Golaknath vs State of Punjab-1967

   Golaknath vs State of Punjab-1967. This 1967 Supreme Court judgment held that Parliament cannot abridge Fundamental Rights, but it did not propound the basic structure doctrine. Hence, this option is incorrect.

3. C

   Chitralekha vs State of Mysore-1964

   Chitralekha vs State of Mysore-1964. This 1964 case dealt with the criteria for admission to medical colleges and the scope of backward classes, having no relevance to the basic structure of the Constitution. Therefore, this option is incorrect.

4. D

   Yusuf vs State of Bombay-1954

   Yusuf vs State of Bombay-1954. This 1954 case related to the Bombay Prohibition Act and gender discrimination provisions under Article 15, rather than the basic structure of the Constitution. Thus, this option is incorrect.

Summary. Official key is (a) Kesavananda Bharti vs State of Kerala-1973. The Supreme Court propounded the concept of the basic structure of the Constitution in this historic 1973 judgment. While earlier cases like Golaknath dealt with the amending power of Parliament, it was the 13-judge bench in Kesavananda Bharati that decisively limited parliamentary sovereignty. This doctrine ensures that core constitutional values remain intact despite amendments. Therefore, option (a) is the correct choice.