Refer to the input text as context and select the correct relationship between 'Syriza' and 'ATHENS' from the available options.
Options: stock exchange, owner of, headquarters location, operator

ATHENS Aug 21 Greece's new Popular Unity party of far-left rebels from the leftist Syriza party will seek a mandate to form a government as the third-biggest group in parliament, a senior party lawmaker told Reuters on Friday.
headquarters location