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
[{'content': 'Measures of dispersion all except \nSelect and explain. \nA. Correlation and regression, B. Mean or average deviation, C. Standard deviation, D. Range', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]