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 50 year old male patient complains of tremors in his hand while working. Patient is a dentist and is working since 25 years. Lab investigations reveal urine mercury level at 200  microgm/L. Which of the following symptoms would been seen in this patient? \nSelect and explain. \nA. Irritability, B. Kidney inflammation, C. Swollen gums, D. Nervous system disturbance', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]