Consider the following statements about the European Union : I. The European Union was known earlier as the European Community. II. The Single European Act (1986) and the Maastricht Treaty were milestones in its formation. III. Citizens of European Union countries enjoy dual citizenship. IV. Switzerland is a member of the European Union. Which of the above statements are correct

Consider the following statements about the European Union : I. The European Union was known earlier as the European Community. II. The Single European Act (1986) and the Maastricht Treaty were milestones in its formation. III. Citizens of European Union countries enjoy dual citizenship. IV. Switzerland is a member of the European Union. Which of the above statements are correct ?