This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
P wave is due to: 
Select and explain. 
A. Atrial depolarization, B. Atrial repolarization, C. Ventricular depolarization, D. Ventricular repolarization
A: Atrial depolarization
Answer: A: Atrial depolarization 
Explanation: Answer is A (Atrial Depolarization) P wave is produced due to atrial depolarization. Intervals Events in the Hea During Interval P wave Atrial depolarization PR interval Atrial depolarization and conduction through AV node QRS duration Ventricular depolarization and atrial repolarization QT interval Ventricular depolarization plus ventricular repolarization ST interval (QT minus QRS) Ventricular repolarization