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: Physiology
QRS complex indicates 
Select and explain. 
A. Atrial repolarization, B. Atrial depolarization, C. Ventricular repolarization, D. Ventricular depolarization
D: Ventricular depolarization
Answer: D: Ventricular depolarization 
Explanation: None