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
[{'content': 'Water lily sign is seen in \nSelect and explain. \nA. TB, B. Aspergillosis, C. Hydatid cyst, D. Cryptococcosis', 'role': 'user'}, {'content': "Answer: C \nExplanation: Classical signs of pulmonary hydatid cyst on chest X-rayUncomplicated hydatid cystComplicated hydatid cystWell circumscribed round radio-opacity (resembling canon ball on AP and rugby ball on lateral projection)Crescent signPolycyclic and bilobed appearanceCumbo or double arch signSlot sign (impending rupture)Waterlily or camelotte signRising sun signDry cyst sign(Ref: Chapman and Nakielny's Aids to Radiological Differential Diagnosis 6thEtd, page no.82)", 'role': 'assistant'}]