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': 'Under stable conditions, the relationship between incidence (I), prevalence (P), and duration (D) is given as \nSelect and explain. \nA. P = I x D, B. I = P x D, C. P = I + D, D. I = P + D', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Prevalence = Incidence x Duration of illnessex: if the duration of illness increase (chronic diseases) prevalence increases', 'role': 'assistant'}]