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

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