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': 'Sex can be established by examining hair root cells for the presence of: \nSelect and explain. \nA. Davidson body, B. Barr body, C. Golgi body, D. Medullary index', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Barr body', 'role': 'assistant'}]