A nurse is reinforcing teaching with a newly licensed nurse about reading a client's ECG tracing. The nurse should include in the teaching that which of the following ECG components represent the time it takes for ventricular depolarization and repolarization?

A. QRS complex: The QRS reflects ventricular depolarization only (ventricular contraction); it does not include repolarization. B. PR interval: PR interval represents conduction time from atrial depolarization through the AV node to the start of ventricular depolarization; it does not represent ventricular repolarization. C. QT interval: The QT interval spans the beginning of ventricular depolarization through ventricular repolarization (total ventricular electrical systole). D. ST segment: The ST segment represents the interval between ventricular depolarization and repolarization (early repolarization phase) but not the full depolarization plus repolarization period.