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

Correct Option (D):

The correct match for the organizations and their headquarters is as follows:

• International Atomic Energy Agency (IAEA) is headquartered in Vienna, Austria.
• International Telecommunication Union (ITU) is headquartered in Geneva, Switzerland.
• Council of the European Union is headquartered in Brussels, Belgium.
• Organisation for Economic Cooperation and Development (OECD) is headquartered in Paris, France.

Therefore, the correct combination is A-4, B-2, C-1, D-3.

Incorrect Options:

Options 1, 2, and 3 are incorrect as they contain inaccurate pairings of organizations with their headquarters. For example, Option 1 incorrectly links the International Atomic Energy Agency to Brussels, Option 2 incorrectly links the Organisation for Economic Cooperation and Development to Geneva, and Option 3 contains multiple misattributions. The correct headquarters for each organization are unique and established, as outlined in the correct option explanation.