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: Radiology
[{'content': 'Most common presentation of radiation carditis is – \nSelect and explain. \nA. Pyogenic Pericarditis, B. Pericardial Effusion, C. Myocardial Fibrosis, D. Atheromatous Plaque', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Pericardial involvement is the most common and includes pericardial effusion and constrictive pericarditis.', 'role': 'assistant'}]