This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
[{'content': 'During skeletal muscle contraction \nSelect and explain. \nA. A band shoen, B. Both H & I band shoen, C. Both A & I band shoen, D. Both A & H band shoen', 'role': 'user'}, {'content': 'Answer: B \nExplanation: During muscle contraction, two Z lines come closer, A band remains constant, length of H & I band decreases.Ref: Guyton; 13th edition', 'role': 'assistant'}]