Answer:
The correct answer is : D. isoelectric line.
Step-by-step explanation:
ECG interpretation requires the analysis of various waves and curves and their characteristic. There are different type of waves and curves that can be found and analyzed in ECG such as P- wave, T wave, PR interval and others.
All these curves and interval shows electrical activities generating by the repolarization and depolarization of atria and ventricles of heart.
Base line or isoelectric line shows a flat line which have no electric activity as there is no negative or positive charge to create deflection.
Thus, the correct answer is : D. isoelectric line.