The South Asian country that is part of India's Act East policy is:

Bangladesh

The correct answer is Option 3- Bangladesh

The South Asian country that is part of India's Act East policy is Bangladesh.

Despite their differences, India and Bangladesh do cooperate on many issues. Economic relations have improved considerably in the last 20 years. Bangladesh is a part of India’s Look East (Act East since 2014) policy that wants to link up with Southeast Asia via Myanmar. On disaster management and environmental issues, the two states have cooperated regularly. In 2015, they exchanged certain enclaves. Efforts are on to broaden the areas of cooperation further by identifying common threats and being more sensitive to each other’s needs.