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
Longest acting L.A 
Select and explain. 
A. Bupivacaine, B. Tetracaine, C. Xylocaine, D. Procaine
B: Tetracaine
Answer: B: Tetracaine 
Explanation: B i.e. Tetracaine