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
Dose of thiopentone used to prevent arterial spasm on intra-arterial injection 
Select and explain. 
A. 5%, B. 2.50%, C. 2%, D. 1.50%
B: 2.50%
Answer: B: 2.50% 
Explanation: 2.5% thiopentone is used to prevent arterial spasm on intra-arterial injection