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: Physiology
Speed of conduction is fastest in: 
Select and explain. 
A. AV node, B. SA node, C. Bundle of His, D. Purkinje system
D: Purkinje system
Answer: D: Purkinje system 
Explanation: D i.e. Purkinje System