Analyze the relationship between 'Syriza' and 'Alexis Tsipras' within the context of the input sentence.
Options: chairperson, parent organization, stock exchange, industry

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