Which of the following provision of the Indian Constitution deals with promoting International Peace and Security?

The correct option is Article 51.

Article 51 of the Indian Constitution, which is part of the Directive Principles of State Policy (Part IV), explicitly directs the State to promote international peace and security. It states that the State shall endeavor to:
1. Promote international peace and security.
2. Maintain just and honorable relations between nations.
3. Foster respect for international law and treaty obligations in the dealings of organized peoples with one another.
4. Encourage settlement of international disputes by arbitration.

To understand why the other options are incorrect, here is a brief overview of what they represent:
- Article 21: Deals with the Protection of Life and Personal Liberty, which is a Fundamental Right (Part III).
- Article 25: Deals with the Freedom of conscience and free profession, practice, and propagation of religion, also a Fundamental Right (Part III).
- Article 44: Deals with the Uniform Civil Code for the citizens, which is a Directive Principle of State Policy (Part IV) but is not related to international peace.