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: Dental
Who is the chief of WHO ? 
Select and explain. 
A. Tedros Adhanom, B. Harshvardhan, C. António Guterres, D. None of the above
A: Tedros Adhanom
Answer: A: Tedros Adhanom 
Explanation: None