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
[{'content': 'Cardiac msucle functions as both electrical and mechanical syncytium. The structual basis of this ability is \nSelect and explain. \nA. T tubule system, B. Intercalated disks, C. Striated nature of the contractile system, D. Extensive sarcoplasmic reticulum', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]