This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Aaron's sign is seen in 
Select and explain. 
A. Achlasia cardia, B. Hiatus hernia, C. Mediastinum emphysema, D. Acute appendicitis
D: Acute appendicitis
Answer: D: Acute appendicitis 
Explanation: Ans. is 'd' i.e., Acute appendicitis