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': 'The most potent and longest acting anaesthetic agent is: \nSelect and explain. \nA. Dibucaine, B. Tetracaine, C. Bupivacaine, D. Lignocaine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Dubucaine is the most potent, most toxic , and longest acting local anesthetic Cinchocaine or dibucaine is an amide local anesthetic. Among the most potent and toxic of the long-acting local anesthetics, current use of cinchocaine is generally restricted to spinal and topical anesthesia. From KD Tripati 7th edition Page no 367', 'role': 'assistant'}]