Refer to the input text as context and select the correct relationship between 'Syriza' and 'Alexis Tsipras' from the available options.
Options: chairperson, stock exchange, industry, parent organization

ATHENS, Sept 20 The leftist Syriza party of Alexis Tsipras has won 35.54 percent of the vote in Sunday's Greek national election based on 50 percent of votes counted, the Interior Ministry said on its website.
chairperson