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': 'Relationship between incidence and prevalence - \nSelect and explain. \nA. Incidence = Prevalence x Duration, B. Prevalence = Incidence x Duration, C. Incidence = Prevalence + Duration, D. Prevalence = Incidence + Duration', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Prevalence = Incidence duration * Prevalence depends upon 2 factorsi) Incidenceii) Duration of illnessPrevalence - Incidence x mean duration.", 'role': 'assistant'}]