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': 'Dose of thiopentone used to prevent arterial spasm on intra-arterial injection \nSelect and explain. \nA. 5%, B. 2.50%, C. 2%, D. 1.50%', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 2.5% thiopentone is used to prevent arterial spasm on intra-arterial injection', 'role': 'assistant'}]