Utilize the input text as a context reference, choose the right relationship between eurozone and euro from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

The 18 other eurozone member have criticised Mr Tsipras for backing a 'No' vote, warning Greek voters the snap ballot represents a choice between keeping the euro and reverting to the drachma.

Answer: currency