This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'Calculate the prevalence if incidence is 2 cases per 1000 population oer year and mean duration is 4 years - \nSelect and explain. \nA. 8 cases per 1000 population, B. 2 cases per 1000 population, C. 0.5 cases per 1000 population, D. 32 cases per 1000 population', 'role': 'user'}, {'content': 'Answer: A \nExplanation: the relationship between incidence and prevalence can be calculated as,prevalence =incidence*mean duration ,here in this case it equals 2*4 that is 8 cases per 1000 population. ref:park&;s textbook of preventive and social medicine,22nd edition,pg no 58', 'role': 'assistant'}]