Correct option is A
The correct statements from the given options are:
B. The bilateral relationship was upgraded to strategic partnership in 2004.
C. The EU is also one of the largest sources of FDI for India.
India was indeed amongst the first countries to establish diplomatic relations with the European Economic Community (EEC), which later became the European Union (EU), making statement A correct as well. However, the EU is not a member of the UN General Assembly; it has observer status but not full membership, making statement D incorrect.
Therefore, the correct option is (a) A, B & C.