Analyze the relationship between 'Vittorio Colao' and 'Vodafone' within the context of the input sentence.
Options: operator, employer, developer, platform

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.
employer