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': 'Natural history of disease can be studied by ? \nSelect and explain. \nA. Cross sectional study, B. Ecological study, C. Coho study, D. RCT', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Coho study Longitudinal studies are used to study natural history of disease. Among the given options, only coho study is a longitudinal study.", 'role': 'assistant'}]