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
The most potent and longest acting anaesthetic agent is: 
Select and explain. 
A. Dibucaine, B. Tetracaine, C. Bupivacaine, D. Lignocaine
A: Dibucaine
Answer: A: Dibucaine 
Explanation: 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