This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immune system, Subject name: Medicine
[{'content': "Endaeritis obliterans is seen in \nSelect and explain. \nA. Marfan's syndrome, B. Turner's syndrome, C. Neurosyphilis, D. Ankylosing spondylitis", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ref Davidsons 23e p1125', 'role': 'assistant'}]