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
Protein-specific for smooth muscle contraction is 
Select and explain. 
A. Troponin, B. Tropomyosin, C. Myosin, D. Calmodulin
D: Calmodulin
Answer: D: Calmodulin 
Explanation: Calmodulin is the calcium binding protein in the smooth muscle. It is similar to troponin C of Skeletal muscle.(REF: TEXTBOOK OF MEDICAL PHYSIOLOGY GEETHA N 2 EDITION, PAGE NO - 59)