This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Pathology
[{'content': '25 year old male presented with growth in left atrium. Diagnosis? \nSelect and explain. \nA. Rhabdomyoma, B. Myxoma, C. Metastasis, D. Papillary elastosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (b) MyxomaThe left atrium has been opened to reveal the most common primary cardiac neoplasm-an atrial myxoma. These benign masses are most often attached to the atrial wall. They can produce a "ball valve" effect by intermittently occluding the atrioventricular valve orifice.', 'role': 'assistant'}]