A solution of a metal ion when treated with `KI` gives a red precipitate which dissolves in excess `KI` to give a colourless solution. Moreover, the solution of metal ion on treatment with a solution of cobalt (II) thiocyanate gives rise to a deep blue crystalline precipitate. The metal ion is

Options

A. `Pb^(2+)`
B. `Hg^(2+)` salt
C. `Cu^(2+)`
D. `Co^(2+)`

Answer

B