This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
Water lilly appearance in a chest radiograph suggests 
Select and explain. 
A. Metastases, B. Cavitating metastasis, C. Aspergilloma, D. Ruptured hydatid cyst
D: Ruptured hydatid cyst
Answer: D: Ruptured hydatid cyst 
Explanation: .