This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System, Subject name: Radiology
Diagnosis is: 
Select and explain. 
A. Right pneumothorax, B. Left pneumothorax, C. Right hydropneumothorax, D. Left hydropneumothorax
C: Right hydropneumothorax
Answer: C: Right hydropneumothorax 
Explanation: Ans. C Right hydropneumothoraxCXR shows lucent (black) lateral aspect of right hemithorax with air fluid level in it-s/o hydropneumothorax. An expiratory CXR better than an inspiratory CXR for a diagnosis of pneumothorax. CT Thorax is IOC for pneumo/hydro- pneumothorax.