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
Which protein prevents contraction by covering binding sites on action and myosin : 
Select and explain. 
A. Troponin, B. Calmodulin, C. Thymosin, D. Tropomyosin
D: Tropomyosin
Answer: D: Tropomyosin 
Explanation: D i.e. Tropomyosin