During the propogation of a nerve impulse, the action potential results from the movement of :

Question

(1) $Na^+$ ions from extracellular fluid to intracellular fluid

(2) $K^+$ ions from extracellular fluid to intracellular fluid

(3) $Na^+$ ions from intracellular fluid to extracellular fluid

(4) $K^+$ ions from intracellular fluid to extracellular fluid