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: Pathology
[{'content': 'Atrial myxoma commonly arises from \nSelect and explain. \nA. Left ventricle, B. Left atrium, C. Right ventricle, D. Right atrium', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Left atrium", 'role': 'assistant'}]