Which of the Following Represents the Sequence of Ion Movements

Multiple Choice

Which of the following represents the sequence of ion movements that causes an action potential?

A) Sodium ions move into the axon and then potassium ions move out of the axon.
B) Sodium ions move out of the axon and then potassium ions move into the dendrite.
C) Potassium ions move out of the dendrite and then sodium ions move into the axon.
D) Sodium ions move out of the axon and then potassium ions move into the axon.