Utilize the input text as a context reference, choose the right relationship between 'Syriza' and 'Alexis Tsipras' from the options.
Options: business division, chairperson, distribution format, parent organization

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