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: Medicine
[{'content': 'All of the following are the known causes of osteoporosis except : \nSelect and explain. \nA. Fluorosis, B. Hypogonadism, C. Hypehyroidism, D. Hyperparathyroidism', 'role': 'user'}, {'content': "Answer: A \nExplanation: Answer is A (Fluorosis): Fluorosis is associated with `Osteosclerosis' and not with osteoporosis. Hypogonodism, Hypehyrodism and Hyperparathyrodism are all known causes for osteoporosis.", 'role': 'assistant'}]