Take context from the input text and decide on the accurate relationship between 'Syriza' and 'Alexis Tsipras' from the options provided.
Options: distribution format, business division, chairperson, member of

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