Take context from the input text and decide on the accurate relationship between 'Syriza' and 'Alexis Tsipras' from the options provided.
Options: chairperson, distributed by, platform, developer

Greek Prime Minister Alexis Tsipras on Friday reshuffled his government, a day after a major lawmaker mutiny in his radical left Syriza party over a draconian bailout deal.
chairperson