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: Anaesthesia
[{'content': 'During surgery for aortic arch aneurysm under deep hypothermic circulatory arrest, which of the following anesthetic agent administered prior to circulatory arrest that also provides cerebral protection ? \nSelect and explain. \nA. Etomidate, B. Thiopental sodium, C. Propofol, D. Ketamine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Thiopental, etomidate and propofol, all three are cerebroprotective. However, thiopental has maximum cerebroprotective\xa0action.\n"Propofol and etomidate appear to lack the same protective effects as thiopental in focal cerebral ischemia" \xa0\xa0─ Morgan', 'role': 'assistant'}]