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 General Index (.ATG) has fluctuated sharply this year, which has seen left-wing Prime Minister Alexis Tsipras's newly elected Syriza government wrangle with European Union and International Monetary Fund lenders in bitter bailout talks.

Answer: headquarters_location