All of these stains are used in tattooing except:

Ans: A. Osmium blue(Ref Reddy 34/e 1,89, 33/e p92).Osmium blue:Not used for tattooing.Tattoo marks:Design made in skin by multiple puncture wounds with needles or an electric vibrator dipped in colouring matter.Commonly used dyes:Indian ink, carbon (black), cinnabar or vermilion (mercuric sulphide) red, chromic acid (green), indigo, cobalt, Prussian blue (ferric ferrocyanide), ultramarine (blue).Osmium tetroxide:Used in optical microscopy.Stains lipids.Dissolves in fats & reduced by organic materials to elemental osmium.Osmium - An easily visible black substance.