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: Surgery
Extradural haematoma is associated with what % of severe trauma - 
Select and explain. 
A. 36%, B. 10%, C. 77%, D. 96%
B: 10%
Answer: B: 10% 
Explanation: "Epidural hematoma occur in upto 10% of severe head injury cases and are less often associated with underlying cortical damage than are subdural hematomas." - Harrison