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: Surgery
Bupivacaine, a local anaesthetic agent used in the dentistry in the concentration of: 
Select and explain. 
A. 2%, B. 4%, C. 5%, D. 0.50%
D: 0.50%
Answer: D: 0.50% 
Explanation: None