What is the relationship between 'eurozone' and 'euro' in the context of the input sentence.
Options: owner of, currency, industry, owned by

If, under the worse-case scenario, Greece were to lose the support of the European Union and European Central Bank, default on more of its debts and gradually slide out of the eurozone , the country may have to drop the euro as it is currently used in favour of Greek euros, or reintroduce the "drachma", calling it "new drachma".
currency