Analyze the relationship between 'Syriza' and 'Alexis Tsipras' within the context of the input sentence.
Options: parent organization, distribution format, business division, chairperson

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