Explanation:

1st amendment

• When the Indian Constitution came into effect since 26th January 1950, the Communal G.O. was challenged in the Madras High Court on the ground that the G.O. Recognising the justification of the revolt, Article 15(4) was inserted into the Indian Constitution through the First Amendment in 1951. Article 15(4) capacitates the state to create special arrangements for promoting the interests and welfare of socially and educationally backward classes of the society such as SC and STs.

Hence option 1st is correct.