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: Anatomy
[{'content': "SA node is located in ? \nSelect and explain. \nA. Triangle of Koch's, B. In crista terminalis, C. In membranous pa of interventricular septum, D. Upper pa of interatrial septum", 'role': 'user'}, {'content': 'Answer: B \nExplanation: In crista terminalis', 'role': 'assistant'}]