Analyze the relationship between 'Vittorio Colao' and 'Vodafone' within the context of the input sentence.
Options: owned by, chief executive officer, original broadcaster, employer

Vodafone chief executive Vittorio Colao has promoted the leaders of the company’s biggest European markets to his top table, even as the networks they run are at the centre of talks about a potential combination with Liberty Global (NasdaqGS: LBTYA - news ) .
employer