Answer : 3. "Article-39(d) "
Explanation :

1. 'Equal pay for equal work for both men and women' is mentioned in Article 39 (d) of the Constitution of India.

2. In this article the State has been directed to ensure equal pay to both men and women for equal work.

3. Article 39(d) is a directive principle of state policy, which means it cannot be implemented through legislation. However, the Court may declare laws that violate this Article unconstitutional.