This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Surgery
[{'content': 'Most common cause of sub arachnoid hemorrhage is - \nSelect and explain. \nA. Berry aneurysm rupture, B. Post traumatic, C. Hypertensive bleed, D. Coagulation disorder', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. is \'b\' i.e., Post traumatic Subarachnoid hemorrhage* Although aneurysms are the most common cause of spontaneous subarachnoid haemorrhage, trauma is by far the commonest cause of subarachnoid haemorrhage overall.* In rare cases, a spontaneous aneurysmal haemorrhage immediately precedes a head injury.* Traumatic subarachnoid haemorrhage is managed conservatively."Excluding head trauma, most common cause of subarachnoid hemorrhage is rupture of a saccular (Berry) aneurysm--------- Harrison', 'role': 'assistant'}]