The correct answer is option 2: Directive Principles of State Policy. The Directive Principles of State Policy are a set of guidelines and principles in the Constitution of India that the state should keep in mind while formulating policies and making laws. These principles encompass a wide range of areas including social justice, economic welfare, and the protection of vulnerable sections of society. They aim to promote the idea of a welfare state where the government takes responsibility for the well-being and development of its citizens. The other options mentioned in the question also have significant importance in the Constitution, but they do not specifically address the ideas of a welfare state like the Directive Principles do.