This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Regional anaesthesia, Subject name: Anaesthesia
All of the following are efective topically exxcept- 
Select and explain. 
A. Procaine, B. Cocaine, C. Lidocaine, D. Amethocaine
A: Procaine
Answer: A: Procaine 
Explanation: Procaine is not effective topically because of poor penetration