This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'Calculate IMR if in a population of 100000 there are 3000 live births in a year and 150 infant deaths in the same year – \nSelect and explain. \nA. 75, B. 18, C. 5, D. 50', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Infant mortality rate', 'role': 'assistant'}]