This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory Radiology, Subject name: Radiology
[{'content': 'Luftsichel sign is seen in \nSelect and explain. \nA. Right upper lobe collapse, B. Right middle lobe collapse, C. Left upper lobe collapse, D. Left lower lobe collapse', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Luftsichel sign is a sickle shaped lucency of air seen On Chest Radiographs, Seen in Left Upper lobe collapse with Compensatory Left Lower lobe hyperinflation.', 'role': 'assistant'}]