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: Medicine
Most common cause of spontaneous SAH - 
Select and explain. 
A. Trauma, B. Aneurysm, C. AV malformation, D. Hypertension
B: Aneurysm
Answer: B: Aneurysm 
Explanation: None