Take context from the input text and decide on the accurate relationship between 'Sergio Marchionne' and 'Fiat' from the options provided.
Options: position held, employer, legal form, creator

Franz told Reuters that Fiat Chief Executive Sergio Marchionne had said at a meeting on Monday he foresaw closing Opel's Kaiserslautern engine plant in Germany and other Fiat and Opel manufacturing sites in England and Italy.
employer