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.

The Athens stock market also fell around 3 percent as the country's prime minister looked set to call early elections in a bid to quell a rebellion in his leftist Syriza party and seal support for a tough bailout programme.

Answer: headquarters_location