By Nadia Damouni NEW YORK (Reuters) – Microsoft Corp has narrowed its list of external candidates to replace Chief Executive Steve Ballmer to about five people, including Ford Motor Co chief Alan Mulally and former Nokia CEO Stephen Elop, according to sources familiar with the matter. The worlds largest software maker also has at least three internal candidates on its shortlist, including former Skype CEO Tony Bates, who is now responsible for Microsofts business development, and Satya Nadella, the companys cloud and enterprise chief, the sources said. Microsoft declined to comment on the process and on behalf of the internal candidates.