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': 'Actin filament is not present in which of the band zones? \nSelect and explain. \nA. H band, B. I band, C. M band, D. Z band', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The myosin and actin filaments overlap in peripheral regions of the A band, whereas a middle region (called the H zone) contains only myosin. H-band is the zone of the thick filaments that is not superimposed by the thin filaments.', 'role': 'assistant'}]