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: Ophthalmology
[{'content': 'Triad of exophthalmos, bone lesions, and diabetes insipidus is a feature of \nSelect and explain. \nA. Hand-schuller christian disease, B. Craniofacial dysostosis, C. Mickulicz syndrome, D. Letterer - sieve disease', 'role': 'user'}, {'content': 'Answer: A \nExplanation: HSCD is associated with multifocal langerhans cell histiocytosis.\nTriad:\n\nExophthalmos\nLytic bone lesions\nDiabetes insipidus.', 'role': 'assistant'}]