Utilize the input text as a context reference, choose the right relationship between 'Syriza' and 'Alexis Tsipras' from the options.
Options: business division, position held, 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