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': "Cause of Unilateral Hypertranslucent hemithorax \nSelect and explain. \nA. Pleural effusion, B. Pneumonectony, C. Poland's syndrome, D. Collapse", 'role': 'user'}, {'content': "Answer: C \nExplanation: Poland's (U/L congenital absence of pectoral muscles) - thus hypertransluscency.", 'role': 'assistant'}]