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': 'Which of the following is situated in the upper pa of Crista terminalis ? \nSelect and explain. \nA. AV node, B. Bundle of his, C. Right Bundle branch, D. SA node', 'role': 'user'}, {'content': 'Answer: D \nExplanation: SA node', 'role': 'assistant'}]