According to Article 51 of the Indian Constitution, what is the State's endeavour concerning international peace and security?

Maintain just and honourable relations between nations

The correct answer is Option 3 - Maintain just and honourable relations between nations

The Article 51 of the Indian Constitution lays down some Directive Principles of State Policy on ‘Promotion of international peace and security’.

“The State shall endeavour to –
(a) Promote international peace and security
(b) Maintain just and honourable relations between nations
(c) Foster respect for international law and treaty obligations in the dealings of organised people with one another; and
(d) Encourage settlement of international disputes by arbitration.”