Match List I (Organisation) with List II (Headquarters) and select the correct answer using the codes given below the lists

(Organisation) | (Headquarters)
A. International Atomic Energy Agency | 1. Brussels
B. International Telecommunication Union | 2. Geneva
C. Council of the European Union | 3. Paris
D. Organisation for Economic Cooperation and Development | 4. Vienna

To find the correct answer, we match each organization to its headquarters location. The International Atomic Energy Agency (IAEA) is based in Vienna (A-4). The International Telecommunication Union (ITU) is located in Geneva (B-2). The Council of the European Union is headquartered in Brussels (C-1), which is often considered the capital of the EU. Finally, the Organisation for Economic Co-operation and Development (OECD) operates out of Paris (D-3). Matching these pairs results in the sequence 4, 2, 1, 3, which corresponds to option D.