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': 'Which protein prevents contraction by covering binding sites on action and myosin : \nSelect and explain. \nA. Troponin, B. Calmodulin, C. Thymosin, D. Tropomyosin', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. Tropomyosin', 'role': 'assistant'}]