- The 42nd Amendment Act, 1976, added four new Directive Principles of State Policy (DPSPs) to the Constitution: - Article 39(f): To protect children and youth against exploitation and moral and material abandonment. - Article 39A: To provide free legal aid to the poor. - Article 43A: To take steps for the participation of workers in the management of industries. - Article 48A: To protect and improve the environment and safeguard forests and wildlife. - Option A (Equal pay for equal work for both men and women) was already present in Article 39(d) of the original Constitution. - Option C (Right to work, education and public assistance) is mentioned in Article 41 of the original Constitution. - Option D (Securing living wage and human conditions of work to workers) is related to Article 43 of the original Constitution. - Therefore, participation of workers in the management of industries (Article 43A) was the principle added by the 42nd Amendment among the given options.