Final answer:
The T wave represents the repolarization of the ventricles, which is the last phase of ventricular depolarization at the base of the heart.
Step-by-step explanation:
The T wave represents the last phase of the ventricular depolarization at the base of the heart, which is essentially the repolarization of the ventricles. The QRS complex, on the other hand, represents ventricular depolarization and includes the repolarization of the atria as an unseen component because it is masked by the larger electrical activity of the ventricles. Thus, for the question of what represents the last phase of ventricular depolarization, the choice is (c) T wave.