This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Medicine
Retrocardiac lucency with air-fluid level is seen in 
Select and explain. 
A. Hiatus hernia, B. Distal end esophageal obstruction, C. Eventration of diaphragm, D. Zenker's diveiculum
A: Hiatus hernia
Answer: A: Hiatus hernia 
Explanation: The gastric fundus when displaced above the diaphragm, presents as a retrocardiac mass on a chest radiograph. The presence of an air-fluid level in the mass suggests the diagnosis. ref - Harrisons internal medicine 20e pg 2211