Refer to the input text as context and select the correct relationship between 'Syriza' and 'Alexis Tsipras' from the available options.
Options: chairperson, position held, owner of, business division

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