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
[{'content': 'Protein connecting Z-lines to M-lines \nSelect and explain. \nA. Kinin, B. Desmin, C. Titin, D. Actin', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The giant protein titin is thought to play major roles in the assembly and function of muscle sarcomeres. Structural details, such as widths of Z- and M-lines and periodicities in the thick filaments, correlate with the substructure in the respective regions of the titin molecule. Sarcomere rest length, its operating range of lengths, and passive elastic propeies are also directly controlled by the propeies of titin.(Ref: <a href="', 'role': 'assistant'}]