Left-wing Syriza party leader Alexis Tsipras speaks to his supporters at Syriza's partyâ€™s main electoral center in Athens, Sunday, Sept. 20, 2015.
Refer to the input text as context and select the correct relationship between 'Syriza' and 'Alexis Tsipras' from the available options.
Options: director/manager, owner of, chairperson, employer