The correct answer is (b).
Schedule X was inserted in the Indian Constitution by the 25th Amendment Act of 1971. This amendment was passed by the Indian Parliament during the Emergency, which was declared by Indira Gandhi in 1975. The amendment gave the President of India the power to declare an Emergency, suspend fundamental rights, and assume legislative powers. It also inserted Schedule X into the Constitution, which lists the powers of the President during an Emergency.
The other options are incorrect. The 44th Amendment Act of 1978 repealed the controversial provisions of the 25th Amendment Act, including the power of the President to declare an Emergency. The 42nd Amendment Act of 1976 was also passed during the Emergency, and it made a number of changes to the Constitution, including the addition of a new Fundamental Duties. The 1st Amendment Act of 1951 was the first amendment to the Indian Constitution, and it made a number of changes, including the addition of a new Directive Principle of State Policy.