# Which of the following is most toxic?

$(a)\;Hg^{2+}_2\qquad(b)\;CH_4\qquad(c)\;Hg^{2+}\qquad(d)\;Methyl\;mercury$

Methyl mercury is most toxic.
Methylmercury is the most toxic form. It affects the immune system, alters genetic and enzyme systems, and damages the nervous system, including coordination and the senses of touch, taste, and sight. Methylmercury is particularly damaging to developing embryos, which are five to ten times more sensitive than adults.
Hence (d) is the correct answer.
edited Oct 22, 2017