Blockade of nerve conduction by a local anesthetic is characterized by:
Greater potential to block a resting nerve as compared to a stimulated nerve
Need to cross the cell membrane to produce the block
Large myelinated fibers are blocked before the un myelinated fibers
Cause consistent change of resting membrane potential
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.
Anesthesia