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
When did WHO declare world free of small pox? 
Select and explain. 
A. 1965, B. 1970, C. 1975, D. 1980
D: 1980
Answer: D: 1980 
Explanation: Small pox was declared eradicated in 198i0 by WHO. India was declared free of small pox in 1977. Ref: Park 21st edition, page 132 Chapter: Epidemiology in communicable diseases.