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': 'The threshold limit value of mercury exposures is: \nSelect and explain. \nA. 0.01 mg / m3, B. 0.05 mg/ m3, C. 0.1 mg /m3, D. 0.001 mg /m3', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]