Utilize the input text as a context reference, choose the right relationship between 'Syriza' and 'Alexis Tsipras' from the options.
Options: owner of, stock exchange, distributed by, chairperson

Greece's voters decisively rejected international creditors' tough bailout terms Sunday, but Greek premier and Syriza leader Alexis Tsipras insisted the result does not mean a "rupture" with Europe despite fears it will end in a "Grexit" from the eurozone.
chairperson