Take context from the input text and decide on the accurate relationship between 'Syriza' and 'Alexis Tsipras' from the options provided.
Options: position held, business division, chairperson, owner of

1236 - Greek Prime Minister Alexis Tsipras appeals to his leftist Syriza party's lawmakers to back a tough reforms package after abruptly offering last-minute concessions to try to save the country from financial meltdown.
chairperson