What is the relationship between 'New Democracy' and 'Antonis Samaras' in the context of the input sentence.
Options: chairperson, industry, member of, currency

ATHENS (Reuters) - Former Prime Minister Antonis Samaras announced he was stepping down as leader of Greece's conservative New Democracy opposition party after a strong vote for the 'No' position backed by the leftwing government in Sunday's referendum.
chairperson