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, Greece — Alexis Tsipras is set to receive the formal mandate later Monday to form a Greek government for the second time, after his left-wing Syriza party unexpectedly won a decisive victory in early national elections.

Answer: chairperson