This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiological Study, Subject name: Social & Preventive Medicine
[{'content': 'Point prevalence of a chronic disease is studied best by: \nSelect and explain. \nA. Case control study, B. Cross sectional study, C. Historical cohort, D. Cohort', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans: B (Cross sectional study) Ref: Textbook of Preventive and Social Medicine, K. Park, 22nd edition page no 59Explanation:* Prevalence is an important measure of burden of disease in the community at a point of time or during a period of time. Accordingly they are called point prevalence and period prevalence.', 'role': 'assistant'}]