Which Statement Best Describes Why Atrial Depolarization Is Usually Not

Multiple Choice

Which statement best describes why atrial depolarization is usually not detected on a normal ECG?

A) It occurs at the same time as the QRS complex.
B) The electrodes cannot be placed high enough on the chest to detect the atria.
C) The voltage change in the atria is minimal and therefore does not register on an ECG.
D) The atria are so small and the depolarization happens so quickly that it cannot be detected.
E) The atria do not contract only the AV valves open.