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
Floating tooth sign is seen in: 
Select and explain. 
A. Dentigerous cyst, B. Periapical cyst, C. Aphthous ulcers, D. Histiocytosis x
D: Histiocytosis x
Answer: D: Histiocytosis x 
Explanation: Floating tooth sign is seen with Histiocytosis x, because of erosion of bonyalveoli around the teeth.