The international aircraft identification mark or registration prefix for India is option 2, VT.

Option 1, AT, is not the correct identification mark for India. It is important to note that each country has its unique registration prefix for aircraft.

Option 3, IX, is incorrect. This registration prefix belongs to India`s neighbor, Myanmar (formerly known as Burma).

Option 4, VX, is not the correct identification mark. There is no known country or international aircraft identification with the prefix VX.

It is essential for aircraft to have a distinctive registration prefix to ensure proper identification and adherence to international aviation regulations. The registration prefix VT is allocated to India for this purpose.