Utilize the input text as a context reference, choose the right relationship between New Democracy and Antonis Samaras from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

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.

Answer: chairperson