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: Forensic Medicine
Blue line on the gums is seen in chronic ..... poisoning : 
Select and explain. 
A. Fig, B. Pb, C. Ag, D. All
D: All
Answer: D: All 
Explanation: B i.e. Pb > A i.e. Hg, C i.e. Ag