Analyze the relationship between 'Syriza' and 'Alexis Tsipras' within the context of the input sentence.
Options: business division, director/manager, chairperson, location of formation

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