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': 'Tear drop heart is seen in \nSelect and explain. \nA. Pulmonary Vein obstruction, B. Mitral incompetence, C. Chronic emphysema, D. Constrictive pericarditis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Tear drop heart - Chronic emphysema.\nPentagon shaped heart - Mitral incompetence.', 'role': 'assistant'}]