Which of the following statement is incorrect of ECG of human heart?
 

• A

  It is graphical representation of the electrical activity of the heart during a cardiac cycle.

• B

  The ECG of a person is obtained by using a machine called electrocardiogram.

• C

  To obtain a standard ECG, patient is connected to the machine with three electrical leads.

• D

  Each peak in the ECG is identified with a letter from P to T that corresponds to a specific electrical activity of the heart.