Take context from the input text and decide on the accurate relationship between 'Syriza' and 'Alexis Tsipras' from the options provided.
Options: chairperson, subsidiary, legal form, location of formation

Prime Minister Alexis Tsipras was heavily reliant on support from the Opposition in getting the vote to pass - following dissent from radical left hardliners within the governing Syriza party.
chairperson