This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Regional Anesthesia, Subject name: Anaesthesia
[{'content': 'Which of the following ester local anesthetics undergo hepatic metabolism- \nSelect and explain. \nA. Procaine, B. Cocaine, C. Benzocaine, D. Tetracaine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ester LA are predominantly metabolized by Pseudocholinesterase. Ester hydrolysis is very rapid and water soluble metabolite are excreted in urine. In contrast to other ester anesthetics cocaine is paially metabolized in the liver and paially excreted unchanged in urine.', 'role': 'assistant'}]