Step 1: What is asked.
We need the country that signed a postal sector MoU with India in February 2026.
Step 2: About the MoU.
A postal MoU aims to improve mail services, logistics, and digital postal links between two countries.
Step 3: India's focus.
India works to strengthen postal ties with Southeast Asian countries for better trade and contact.
Step 4: The partner.
In February 2026 India signed this postal MoU with Cambodia.
Step 5: Remove others.
Vietnam, Brazil, and Congo are not the partner in this agreement.
Step 6: Conclusion.
So the country is Cambodia.
Answer: Cambodia