Match List I with List II

List I		List II
A	P wave	I	Heart muscles are electrically silent.
B	QRS complex	II	Depolarisation of ventricles.
C	T wave	III	Depolarisation of atria.
D	T-P gap	IV	Repolarisation of ventricles.

Choose the correct answer from the options given below :

The correct answer/option is A-III, B-II, C-IV, D-I.

To understand the pairing between the components of an electrocardiogram (ECG) in List I and their corresponding physiological events in List II, let us analyze each item step-by-step:

1. A. P wave
The P wave is the first deflection in a normal ECG. It represents the depolarization of the atria (atrial depolarization), which leads to the contraction of both atria. Therefore, A matches with III.

2. B. QRS complex
The QRS complex represents the depolarization of the ventricles (ventricular depolarization), which initiates ventricular contraction. Therefore, B matches with II.

3. C. T wave
The T wave represents the return of the ventricles from the excited to the normal state, which is the repolarization of the ventricles (ventricular repolarization). Therefore, C matches with IV.

4. D. T-P gap
The T-P segment or gap represents the time interval from the end of ventricular repolarization (T wave) to the beginning of the next atrial depolarization (P wave). During this period, the entire heart is in diastole (relaxation phase) and the heart muscles are electrically silent. Therefore, D matches with I.

Combining all the correct matches, we get:
A-III, B-II, C-IV, D-I