20. Which of the following statements are accurate?

A. Repolarization of a neuron results from potassium diffusing out of the cell.
B. At rest, excitable cells (e.g. neurons) have a negative charge.
C. Once a depolarization reaches threshold, an action potential will occur and can not be prevented.
D. To reach threshold, cells at rest must depolarize.
E. Sodium diffusing into a neuron will cause depolarization.