The correct answer is option 3: First Amendment Act. The 9th Schedule to the Constitution of India was introduced through the First Amendment Act of 1951.

The First Amendment Act was passed primarily to counteract the Supreme Court`s decision in the case of Shankari Prasad v. Union of India, where it was ruled that the Fundamental Rights could not be judicially reviewed if they were protected by an amendment to the Constitution. This decision had limited the scope of judicial review over laws that violated fundamental rights.

To overcome this limitation, the First Amendment Act added the 9th Schedule to the Constitution. The 9th Schedule provided immunity to laws that were included in it from being challenged in court on the grounds of violation of fundamental rights. This gave the government the power to enact laws that might infringe upon fundamental rights, without the risk of them being struck down by the courts.

In conclusion, the 9th Schedule to the Constitution of India was introduced by the First Amendment Act to protect laws from judicial review if they were included in the schedule.