In the context of the input sentence, determine the relationship between 'Syriza' and 'Alexis Tsipras'.
Options: director/manager, member of, distributed by, chairperson

Greek voters overwhelmingly rejected international creditors' tough bailout terms Sunday, but 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