Greek Prime Minister Alexis Tsipras on Wednesday faced down a major mutiny in his radical left Syriza party and violent protests in the streets of Athens to win parliamentary approval for the tough reforms by creditors.
Utilize the input text as a context reference, choose the right relationship between 'Syriza' and 'Alexis Tsipras' from the options.
Options: chairperson, subsidiary, owner of, founded by