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
Which of the following diseases is under international surveillance: March 2010 
Select and explain. 
A. Influenza, B. Malaria, C. Polio, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Ans. D: All of the above