This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
P- wave is absent in - 
Select and explain. 
A. WPW syndrome, B. Atrial Fibrillation, C. Ventricular Fibrillation, D. Atrial Tachycardia
B: Atrial Fibrillation
Answer: B: Atrial Fibrillation 
Explanation: None