Burtonian line is seen in poisoning by -
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).
Lead
Mercury
Copper
Morphine
Toxicology