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
[{'content': 'AV nodal delay is: \nSelect and explain. \nA. 0.2 sec, B. 0.13 sec, C. 0.01 sec, D. 0.3 sec', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Velocity of impulses at different parts of conductive system:\n\nAtrial muscle fibers : 0.3 meter/second\nInternodal fibers : 1.0 meter/second\nAV node : 0.05 meter/second\nBundle of His : 0.12 meter/second\nPurkinje fibers : 4.0 meter/second\nVentricular muscle fibers : 0.5 meter/second\n\nThus, the velocity of impulses is maximum in Purkinje fibers and minimum at AV node.', 'role': 'assistant'}]