<prompt> In a normal electrocardiogram ECG or EKG,The P wave results from repolarization of the atria.The QRS complex results from depolarization of the ventricles.The T wave represents repolarization of the auricles.During the P-R interval, the ventricle contract.  <response>: B: The QRS complex consists of three individual waves: the Q, R, and S waves. The QRS complex results from depolarization of the ventricles, and the beginning of the QRS complex precedes ventricular contraction.A: The P wave results from depolarization of the atrial myocardium, and the beginning of the P wave precedes the onset of atrial contraction.C: The T wave represents the repolarization of the ventricles, and the beginning of the T wave precedes ventricular relaxation.D: During the P-R interval, the atria contract and begin to relax. 