Utilize the input text as a context reference, choose the right relationship between Syriza and Alexis Tsipras 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.

Greece's government on Tuesday submitted tough bailout terms demanded by eurozone creditors to parliament, as Prime Minister Alexis Tsipras battled for support for the draconian reforms from his ruling anti-austerity Syriza party.

Answer: chairperson