Greek Prime Minister Alexis Tsipras had urged his fellow members of parliament to vote 'yes' and survived despite up to 42 rebel votes or abstentions from his Syriza party's MPs, including a 'no' vote from former finance minister Yannis Varoufakis.
In the context of the input sentence, determine the relationship between 'Syriza' and 'Alexis Tsipras'.
Options: publisher, chief executive officer, business division, chairperson