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

Whether Syriza leader Alexis Tsipras or his New Democracy opponent Evangelos Meimarakis triumph in the election on Sunday that is too-close-to-call, Mr Dallara said volatility induced by Greece "is highly likely to rear its head again.
chairperson