This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nose and paranasal sinuses, Subject name: ENT
[{'content': 'What is a Rhinolith: \nSelect and explain. \nA. Foreign body in nose, B. Stone in nose, C. Deposition of calcium around foreign body in nose, D. Misnomer', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Rhinoliths are calcareous masses which result due to deposition of salts-like calcium and magnesium carbonates and phosphates around the nucleus of a foreign body. Ref Dhingra 6/e,p 161.', 'role': 'assistant'}]