This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
[{'content': 'All of the following conditions are known to cause diabetes insipidus except - \nSelect and explain. \nA. Multiple sclerosis, B. Head injury, C. Histiocytosis, D. Viral encephalitis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Causes of Central Diabetes insipidus Causes of Nephrogenic Diabetes insipidus ref - Researchgate.net', 'role': 'assistant'}]