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
The given CXR shows the presence of: 
Select and explain. 
A. Hydro-pneumothorax, B. Pleural effusion, C. Lung abscess, D. Collapse
A: Hydro-pneumothorax
Answer: A: Hydro-pneumothorax 
Explanation: 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