This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Toxicology, Subject name: Forensic Medicine
Burtonian line is seen in poisoning by - 
Select and explain. 
A. Lead, B. Mercury, C. Copper, D. Morphine
A: Lead
Answer: A: Lead 
Explanation: Ans. is 'a > b & c' i.e., Lead > Mercury & Copper * Burtonian line is blue line, which is seen on upper gums in lead poisoning.* Similar blue line (but not called burtonian line in these cases) is also seen in poisoning with Mercury (Hg), Copper (Cu), Silver (Ag), bismuth (Bi), and Iron (Fe).