What is the relationship between Syriza and Athens 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.

Despite the prospect of a confidence vote after some lawmakers from the ruling Syriza party rebelled over a new bailout deal, the Athens stock market was up 0.4 percent, having given up the bulk of earlier gains.

Answer: headquarters_location