In the context of the input sentence, determine the relationship between 'Syriza' and 'Alexis Tsipras'.
Options: distributed by, chairperson, owner of, stock exchange

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