Utilize the input text as a context reference, choose the right relationship between Sergio Marchionne and Fiat 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.

Thomson Reuters Chief Executive of Fiat Chrysler Sergio Marchionne speaks during the first press preview day of the North American International Auto Show in Detroit

Answer: employer