Utilize the input text as a context reference, choose the right relationship between Syriza and Athens from the options. Options: 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.

Tsipras held meetings with his radical leftist Syriza party on Tuesday, as he faced the tough task of selling a new bailout deal that requires Athens to push through draconian reforms within just two days.

Answer: headquarters_location