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
Cerebral Ischemia occur when cerebral blood flow is less than - 
Select and explain. 
A. 10 ml/100g/minute, B. 20 ml/100g/minute, C. 40 ml/100g/minute, D. 50 ml/100g/minute
B: 20 ml/100g/minute
Answer: B: 20 ml/100g/minute 
Explanation: None