This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Surgery
[{'content': 'Extradural haematoma is associated with what % of severe trauma \nSelect and explain. \nA. 35, B. 10, C. 25, D. 50', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Epidural hematoma occur in upto 10% of severe head injury cases and are less often associated with underlying coical damage than are subdural hematomas." - Harrison Ref : Harrison 17/e 2599', 'role': 'assistant'}]