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': 'The velocity of conduction in the Purkinje fibers of the heart is \nSelect and explain. \nA. 1 to 4 m/sec, B. 5 to 8 m/sec, C. 9 to 12 m/sec, D. More than 12 m/sec', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]