Utilize the input text as a context reference, choose the right relationship between Martin Winterkorn and Chief Executive Officer 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.

Volkswagen's admission is putting pressure on Chief Executive Officer Martin Winterkorn to repair the reputation of the world's biggest carmaker.

Answer: position_held