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

ATHENS, Sept 1 Greece's Syriza party will scrap a value added tax on private education if voted back to power in a snap election in September, a party statement said on Tuesday evening, as its leader Alexis Tsipras campaigned on the island of Crete.
chairperson