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: Pathology
[{'content': 'Shingles occurs \nSelect and explain. \nA. primary infection, B. is unilateral, C. occurs on movable tissues, D. is bilateral', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]