This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intravenous Anesthetic Agents, Subject name: Anaesthesia
Which of the following is best drug for cerebroprotective? 
Select and explain. 
A. Thiopentone, B. Propofol, C. Ketamine, D. Etomidate
A: Thiopentone
Answer: A: Thiopentone 
Explanation: All intravenous anaesthetic agent causes a decrease in cerebral oxygen consumption thus are cerebroprotective. Thiopentone decrease upto 50% of decline in CMRO2. Because the decrease in systemic aerial pressure is usually less than the reduction in ICP, thiopentone should improve cerebral perfusion and compliance.