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: Unknown
[{'content': 'Neurofibromatosis 1 criteria except \nSelect and explain. \nA. Brain tumor, B. Acoustic neuromas, C. Pseudoarthrosis, D. Café-au-lait spots', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ref. API Textbook of Medicine. Pg. 219', 'role': 'assistant'}]