Utilize the input text as a context reference, choose the right relationship between 'Sergio Marchionne' and 'Fiat' from the options.
Options: creator, position held, employer, legal form

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