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

• A
  $K^{+}$ ions from extracellular fluid to intracellular fluid
• B
  $Na^{+}$ ions from intracellular fluid to extracellular fluid
• C
  $K^{+}$ ions from intracellular fluid to extracellular fluid
• D
  $Na^{+}$ ions from extracellular fluid to intracellular fluid