This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Pediatrics
[{'content': 'Localised Langerhans cells histiocytosis affecting head and neck is \nSelect and explain. \nA. Letterer-Siwe disease, B. Pulmonary Langerhans cell histiocytosis, C. Hand-Schuller-Christian disease, D. Eosinophilic granuloma', 'role': 'user'}, {'content': "Answer: D \nExplanation: d. Eosinophilic granuloma(Ref: Nelson's 20/e p 2484-2489, Ghai 8/e p 620-623)Eosinophilic granuloma: Bone lesions, with no visceral involvement; Localised; affects head and neck", 'role': 'assistant'}]