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': 'Most distinguishable feature between skeletal and smooth muscle is the presence of ------ in smooth muscle \nSelect and explain. \nA. Troponin, B. Tropomyosin, C. Myosin, D. Actin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Actin, myosin & tropomyosin are present in both skeletal muscle & smooth muscle, but troponin is absent in smooth muscle', 'role': 'assistant'}]