Greek Prime Minister Alexis Tsipras on Wednesday had to face down a major mutiny in his radical left Syriza party, and violent protests in the streets of Athens, to win parliamentary approval for the draconian reforms demanded in the bailout package.
In the context of the input sentence, determine the relationship between 'Syriza' and 'Alexis Tsipras'.
Options: owner of, manufacturer, industry, chairperson