What is the relationship between Vittorio Colao and Vodafone 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.

LONDON, July 21 (Reuters) - Vodafone said the bosses of its four biggest European markets would report directly to chief Vittorio Colao to speed up decision making in fast-changing markets, after it decided to scrap its European regional management structure.

Answer: employer