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': 'Normal AV delay of 0.1 seconds is due to: \nSelect and explain. \nA. Decrease in amplitude of firing, B. Resistance offered by myocytes, C. Decrease in number of gap junctions, D. Lack of tight junctions', 'role': 'user'}, {'content': 'Answer: C \nExplanation: AV node\xa0conduction\xa0velocity is lowest because\xa0of:\xa0Less\xa0number\xa0of\xa0gap\xa0junctions, small diameter fibers and slow type AP.', 'role': 'assistant'}]