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

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