This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pneumothorax, Subject name: Medicine
[{'content': 'The given CXR shows the presence of: \nSelect and explain. \nA. Hydro-pneumothorax, B. Pleural effusion, C. Lung abscess, D. Collapse', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Hydro-pneumothorax - On Erect chest radiography, it shows an air-fluid level. On Supine radiography, sharp pleural line is bordered by increased opacity lateral to it within the pleural space. Pleural effusion :- Blunting of CP angle and presence of Meniscus sign. Lung collapse :- lung appears to be collapsed to one side', 'role': 'assistant'}]