Utilize the input text as a context reference, choose the right relationship between Vittorio Colao and Vodafone 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.

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