What is the relationship between Sergio Marchionne and Fiat in the context of the input sentence. Choose an answer from: 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.

Several months ago, Fiat Chrysler CEO Sergio Marchionne sent Barra an email saying he wanted the two companies to merge, a notion Barra has consistently said she and the company's board of directors are not interested in.

Answer: employer