In the context of the input sentence, determine the relationship between 'Syriza' and 'Alexis Tsipras'.
Options: chairperson, business division, position held, 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