This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
The regulator proteins are 
Select and explain. 
A. Troponin, B. Tropomyosine, C. Both, D. None
C: Both
Answer: C: Both 
Explanation: Both troponin and tropomyosine are the regulator proteins for muscle contraction Ref:Guyton and Hall textbook of medical physiology 12th edition ,pag number:86,87