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
Most common deviation used in social medicine is 
Select and explain. 
A. Mean, B. Range, C. Variance, D. Standard deviation
D: Standard deviation
Answer: D: Standard deviation 
Explanation: "Standard deviation is most common and generally most appropriate measure of dispersion (variation)".-Park