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: Forensic Medicine
[{'content': 'Xiphoid process fuses with sternum after: DNB 09 \nSelect and explain. \nA. 60 years, B. 40 years, C. 30 years, D. 20 years', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. 40 years', 'role': 'assistant'}]