Utilize the input text as a context reference, choose the right relationship between 'Syriza' and 'Alexis Tsipras' from the options.
Options: director/manager, location of formation, chairperson, business division

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.
chairperson