This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Concept of health and disease, Subject name: Social & Preventive Medicine
[{'content': 'If you desire to study the incidence of diarrhea in a community which study method would you like to opt for \nSelect and explain. \nA. Cross-sectional study, B. Coho study, C. Case control study, D. Double blind placebo study', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The aim of study would be to find risk factors. It is a prospective study.In the coho study, we can determine incidence rates.&;A well-designed coho study is considered the most reliable means of showing an association between a suspected risk factor and subsequent disease"Park 23rd edition pg: 76', 'role': 'assistant'}]