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
Which metal poisoning can cause the below nail changes? 
Select and explain. 
A. Mercury, B. Lead, C. Arsenic, D. Copper
C: Arsenic
Answer: C: Arsenic 
Explanation: The image shows the presence of white lines of discolouration across the nails i.e "Mees lines", characteristically seen in cases of Acute Arsenic poisoning.