In the context of the input sentence, determine the relationship between 'Syriza' and 'Alexis Tsipras'.
Options: currency, publisher, chairperson, legal form

Prime Minister Alexis Tsipras and his ruling Syriza party's major issue with bailout proposals so far has been that they effectively turn Greece into a zombie country, stumbling along the poverty line and existing solely to pay off its heavy debts.
chairperson