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
AV nodal delay is: 
Select and explain. 
A. 0.2 sec, B. 0.13 sec, C. 0.01 sec, D. 0.3 sec
B: 0.13 sec
Answer: B: 0.13 sec 
Explanation: Velocity of impulses at different parts of conductive system:

Atrial muscle fibers : 0.3 meter/second
Internodal fibers : 1.0 meter/second
AV node : 0.05 meter/second
Bundle of His : 0.12 meter/second
Purkinje fibers : 4.0 meter/second
Ventricular muscle fibers : 0.5 meter/second

Thus, the velocity of impulses is maximum in Purkinje fibers and minimum at AV node.