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': 'A 29 year old female patient complains of decayed tooth. Patient is 7 months pregnant and gives history of cavity preparation and restoration with amalgam done with 16,17,26,27,37. Intra-oral examination reveals proximal caries with 26. The upper limit of urinary mercury in this patient is?\u200b \nSelect and explain. \nA. 1 microgm/L\u200b, B. 2 microgm/L\u200b, C. 3 microgm/L\u200b, D. 4 microgm/L\u200b', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]