What is the expected effect on nerve impulse transmission if extracellular sodium were acutely lowered in a neuron while intracellular potassium remained unchanged?

Reduced ability to generate action potentials because the reduced extracellular sodium decreases the inward sodium current during depolarization, slowing nerve impulse transmission.

Complete and irreversible block of all nerve activity immediately because sodium is the only ion that supports any electrical signal in neurons and muscle tissue.

No change in nerve conduction because potassium is the main ion responsible for depolarization and sodium levels do not influence neuronal electrical activity.

Increased frequency of action potentials because lower extracellular sodium makes the membrane more excitable and more likely to depolarize spontaneously.