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': "Causes of a cavitating lesion in the chest radiograph are all except - \nSelect and explain. \nA. Hamartoma, B. Pulmonary infarction, C. Squamous carcinoma of the bronchus, D. Caplan's syndrome", 'role': 'user'}, {'content': "Answer: A \nExplanation: Haematoma (not hamartoma) causes lung cavitation.\nPulmonary infarct, squamous cell carcinoma of lung, RA & Caplan's syndrome can also cause lung cavitation.", 'role': 'assistant'}]