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: Medicine
[{'content': 'Following are findings of GBS except \nSelect and explain. \nA. Albumino-cytological dissociation, B. Helicobacter pylori is frequent cause, C. Perivenous lymphatic infiltrates, D. Febrile polyneuritis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Antecedent infection with campylobacter jejuni is known to be frequently associated with GBS', 'role': 'assistant'}]