North Atlantic Treaty Organization -- military alliance of democratic states in Europe and North America
O NATO
O NAFTA
EU
O ASEAN

Correct answer is NATO.

Explanation:

NATO is a military alliance created after WW2 (in 1949) by United States, Great Britain and countries of similar foreign policy. Today has 30 countries.

NAFTA is the North American Free Trade Agreement, and therefore this is not correct answer.

EU is European Union, so this is also not correct.

ASEAN is Association of Southeast Asian Nations, so this is also not correct answer.