This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Radiology
Interpret the following chest Xray 
Select and explain. 
A. PDA, B. Pericardial effusion, C. Constrictive pericarditis, D. Emphysema
B: Pericardial effusion
Answer: B: Pericardial effusion 
Explanation: .