This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anesthesia, Subject name: Pharmacology
[{'content': 'Which local anesthetic has a shoer duration of action? \nSelect and explain. \nA. Lidocaine, B. Procaine, C. Bupivacaine, D. Ropivacaine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Procaine has least duration among the following. Procaine,Bencocaine,chlorprocaine all of them are sho acting LA. <img class="fr-fic fr-dib" style="width: 300px;" src=" />Ref: Katzung 13e pg: 443', 'role': 'assistant'}]