The correct answer is: a) Economic and social justice.
The Directive Principles of State Policy are a set of principles enshrined in the Indian Constitution. They are not enforceable by the courts, but the government is expected to follow them in making laws and policies. The Directive Principles aim to promote economic and social justice, as well as to secure a decent standard of living for all citizens.
Option b) is incorrect because the Directive Principles do not aim to restrict individual freedoms. In fact, they often promote individual freedoms by ensuring that everyone has access to basic necessities such as food, water, and education.
Option c) is incorrect because the Directive Principles do not aim to centralize power. In fact, they often promote decentralization by encouraging local governments to take responsibility for providing basic services to their citizens.
Option d) is incorrect because the Directive Principles do not aim to promote religious doctrines. In fact, they are secular in nature and do not promote any particular religion.