What is the relationship between Syriza and Alexis Tsipras in the context of the input sentence. Choose an answer from: 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.

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.

Answer: chairperson