What Is the Difference Between the Eurozone and the European

What is the difference between the Eurozone and the European Union (EU) ?

A) There is no difference; they are simply different terms for the same thing.
B) The Eurozone refers to only those member countries that are geographically connected, having common borders within the EU, while the EU includes all member countries.
C) The Eurozone includes all countries within the continent of Europe, while the EU includes only the European countries that have joined the European Union.
D) The Eurozone includes all countries that adopted the Euro as their official currency, while the EU includes all countries that belong to the European Union.