This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anaesthesia, Subject name: Pharmacology
Naturally occurring local anesthetic:(1997) 
Select and explain. 
A. Cocaine, B. Procaine, C. Lignocaine, D. Bupivacaine
A: Cocaine
Answer: A: Cocaine 
Explanation: aRef: KDT, 5th ed, p. 324 & 4th ed, p. 165