FILE PHOTO: A logo of Italian multinational energy company Enel is seen at the Milan's headquarter, Italy, February 5, 2020. REUTERS/Flavio Lo Scalzo/File Photo MADRID : Europe's biggest utility Enel is preparing to take full control of fibre optic network operator Ufinet by exercising an option to buy the 79per cent owned by private equity firm Cinven, three sources with knowledge of the matter said.