This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
QRS complex is due to? 
Select and explain. 
A. Ventricular repolarization, B. Ventricular depolarization, C. Atrial repolarization, D. Atrial depolarization
B: Ventricular depolarization
Answer: B: Ventricular depolarization 
Explanation: QRS complex is due to right and left ventricular depolarization. Depolarisation of ventricle of hea occurs simultaneously bundle of His and Purkinje fibres.(Ref: General pathology in Textbook of pathology HARSH MOHAN 6th Editon)