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
Skeletal muscles 
Select and explain. 
A. Contracts when calcium is taken up by sarcoplasmic reticulum, B. Contracts when actin and myosin filaments shorten, C. Contraction is initiated by calcium binding to troponin, D. Contraction is initiated by calcium binding to tropomyosin
C: Contraction is initiated by calcium binding to troponin
Answer: C: Contraction is initiated by calcium binding to troponin 
Explanation: None