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: Dental
[{'content': 'Cholesterol crystals are occasionally present in which of the following Zone? \nSelect and explain. \nA. Zone of contamination, B. Zone of irritation, C. Zone of necrosis, D. Zone of stimulation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]