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.

Nobel prize winning economist Paul Krugman, a vocal supporter of Athens in its long-running bailout saga, said Sunday that he "may have overestimated the competence of the Greek government," suggesting Syriza staged the showdown without having a Plan B.

Answer: headquarters_location