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: Social & Preventive Medicine
[{'content': 'Decreased teeth enamel is seen in all except: \nSelect and explain. \nA. Hyperparathyroidism, B. Cushing syndrome, C. Fluorosis, D. Ostcomalacia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. Fluorosis', 'role': 'assistant'}]