In the context of the input sentence, determine the relationship between 'Syriza' and 'Alexis Tsipras'.
Options: chairperson, distribution format, parent organization, 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