Which of the following countries is not a member of European Union?

The European Union (EU) is a political and economic union of certain European states. At present, it has 28 member states: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Ireland, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, Portugal, Romania, Spain, Slovakia, Slovenia, Sweden and the United Kingdom (UK). 

Clearly, Norway is not a member of EU.