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': 'Investigation of choice to differentiate pericardial effusion and dilatation of hea: \nSelect and explain. \nA. Echocardiography, B. Angio cardiography, C. MR!, D. CT', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Echocardiography', 'role': 'assistant'}]