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': 'Which metal poisoning can cause the below nail changes? \nSelect and explain. \nA. Mercury, B. Lead, C. Arsenic, D. Copper', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The\xa0image shows the presence of white lines of discolouration across the nails i.e "Mees lines", characteristically seen in cases of Acute Arsenic poisoning.', 'role': 'assistant'}]