What is the relationship between 'Syriza' and 'Alexis Tsipras' in the context of the input sentence.
Options: chairperson, founded by, manufacturer, developer

The new "preliminary draft" analysis of Greece's finances highlighted the deterioration that has taken place since Prime Minister Alexis Tsipras and his anti-austerity Syriza party took power at the beginning of 2015.
chairperson