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': 'In skeletal muscle, actin is bound to Z line by \nSelect and explain. \nA. Titin, B. Desmin, C. Actinin, D. Tropomyosin', 'role': 'user'}, {'content': "Answer: C \nExplanation: Actinin binds actin to the Z lines. Titin connects the Z lines to the M lines and provides scaffolding for the sarcomere. Desmin adds structure to the Z lines in pa by binding the Z lines to the plasma membrane. Tropomyosin molecules are long filaments located in the groove between the two chains in the actin (Figure 5-3). (Ref: Ganong's review of medical physiology 23rd Edition page no.96)", 'role': 'assistant'}]