What is the name of the neighboring country of India with which India does not have any major conflict and India is also the biggest source of development aid for that country?

Bhutan

The correct answer is Option 4 - Bhutan

India enjoys a very special relationship with Bhutan too and does not have any major conflict with the Bhutanese government. India is involved in big hydroelectric projects in Bhutan and remains the Himalayan kingdom’s biggest source of development aid.