In the Constitution of India, promotion of international peace and security is included in the

The answer is B. Article 51, placed in Part IV (Directive Principles of State Policy), says the State shall endeavour to promote international peace and security, maintain just and honourable relations between nations, foster respect for international law and treaty obligations, and encourage settlement of international disputes by arbitration.

Why the others fail:

• A (Preamble): it commits to justice, liberty, equality, fraternity and dignity, but it does not contain the international peace directive.
• C (Fundamental Duties): Article 51A lists duties of citizens, such as respecting the Constitution, protecting the environment and developing a scientific temper. None addresses international peace.
• D (Ninth Schedule): it lists central and state laws shielded from judicial review. It is a list of protected laws, not a statement of foreign policy goals.

Core concept: DPSPs are non-justiciable guidance for the State, and Article 51 is the constitutional basis for India's foreign policy. That makes it a useful Mains link to India's stance on international law, arbitration and disputes.

Trap: candidates pick the Preamble because it sounds world-facing about fraternity and dignity. The explicit foreign-policy clause sits in Article 51 under the DPSPs.