<prompt> Burtonian line is seen in poisoning by -LeadMercuryCopperMorphine  <response>: 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. 