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': 'In a ceain population, there were 4050 bihs in the last one year. There were 50 still bihs, 50 infants died within 7 days whereas 150 died within the first 28 days. What is the neonatal moality rate \nSelect and explain. \nA. 50, B. 62.5, C. 12.5, D. 49.4', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. a. 50', 'role': 'assistant'}]