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.

ATHENS, Sept 1 Greece's Syriza party will scrap a value added tax on private education if voted back to power in a snap election in September, a party statement said on Tuesday evening, as its leader Alexis Tsipras campaigned on the island of Crete.

Answer: chairperson