In a normal ECG, no separate wave is detected for atrial repolarization because
a. the amount of atrial tissue is too little for the current to be detected by the ECG electrodes.
b. the time period between atrial depolarization and repolarization occurs too rapidly.
c. atrial repolarization and ventricular depolarization are simultaneous, and the expected wave is masked by the QRS complex.
d. None of these.
C
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