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': 'Maternal moility rate is: \nSelect and explain. \nA. Maternal death/100 bihs, B. Maternal death/100 live bihs, C. Maternal death/1000 bihs, D. None', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'None'", 'role': 'assistant'}]