This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Conducting System of Hea, Subject name: Physiology
A 55-year-old man has been diagnosed with Stokes- Adams syndrome. Two minutes after the onset of syncopal attack, which of the following is the pacemaker of the hea? 
Select and explain. 
A. Sinus node, B. A-V node, C. Purkinje fibers, D. Cardiac septum
C: Purkinje fibers
Answer: C: Purkinje fibers 
Explanation: During a Stokes-Adams syndrome attack, total A-V block suddenly begins. After a few seconds, some pa of the Purkinje system beyond the block, usually in the distal pa of the A-V node beyond the blocked point in the node, or in the A-V bundle, begins discharging rhythmically at a rate of 15 to 40 times per minute and acting as the pacemaker of the ventricles. This phenomenon is called ventricular escape.