At the 2007, 2008, and 2009 Consumer Electronics Shows, Microsoft had announced that IPTV services would soon be made available to use through the Xbox 360. In 2007, Microsoft chairman Bill Gates stated that IPTV on Xbox 360 was expected to be available to consumers by the holiday season, using the Microsoft TV IPTV Edition platform. In 2008, Gates and president of Entertainment & Devices Robbie Bach announced a partnership with BT in the United Kingdom, in which the BT Vision advanced TV service, using the newer Microsoft Mediaroom IPTV platform, would be accessible via Xbox 360, planned for the middle of the year. BT Vision's DVR-based features would not be available on Xbox 360 due to limited hard drive capacity. In 2010, while announcing version 2.0 of Microsoft Mediaroom, Microsoft CEO Steve Ballmer mentioned that AT&T's U-verse IPTV service would enable Xbox 360s to be used as set-top boxes later in the year. As of January 2010, IPTV on Xbox 360 has yet to be deployed beyond limited trials.
Try to answer this question if possible (otherwise reply "unanswerable"): Who is the CEO of BT?
unanswerable