This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
Who is the current Secretary General of the UN? 
Select and explain. 
A. Ban Ki-moon, B. Kofi A Annan, C. Boutros Boutros Ghali, D. Boutros Boutros Ghali U Thant
A: Ban Ki-moon
Answer: A: Ban Ki-moon 
Explanation: Ban Ki-moon is the eighth Secretary-General of the United Nations. Mr Ban took office on 1 January 2007. On 21 June 2011, he was unanimously re-elected by the General Assembly and will continue to serve until 31 December 2016. Ref: http://www.un.org/sg/biography.shtml.