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
Blockade of nerve conduction by a local anesthetic is characterized by: 
Select and explain. 
A. Greater potential to block a resting nerve as compared to a stimulated nerve, B. Need to cross the cell membrane to produce the block, C. Large myelinated fibers are blocked before the un myelinated fibers, D. Cause consistent change of resting membrane potential
B: Need to cross the cell membrane to produce the block
Answer: B: Need to cross the cell membrane to produce the block 
Explanation: Essentials of medical pharmacology, seventh edition , page no=361, Local anaesthetics block nerve conduction by decreasing the entry of sodium ions during upstroke of action potential. They interact with a receptor situated within the voltage sentive sodium channel and raise the threshold of channel opening. Hence optuon 2 is the answer since they have to cross the cell membrane to block the nerves.