Answer:
WTO is an intergovernmental organisation ; NAFTA is a 'free trade area' ; EU is an 'Economic Union'
Explanation:
The North American Free Trade Agreement (NAFTA) , European Union (EU) are economies at different level of Economic Integration.
World Trade Organisation is an international intergovernmental organisation, for regulating International Trade - of goods , services , intellectual rights. it also provides framework for trade agreements & dispute settlement. It has 165 member countries,
NAFTA is a 'free trade agreement' between 3 countries : US, Mexico, Canada; which is the lowest form of economic integration - including barrier free trade between the member countries.
EU is an 'Economic Union' between many European countries ; which is the second highest form of economic integration - including barrier free trade, common external tariffs, free labour & capital movement, common monetary & fiscal policy.