# Which metal involves in leaching

$(a)\;Au \\(b)\;Ag \\(c)\; both\;(a)\; and\; (b) \\(d)\;None$

$Au$ and $Ag$ involves in leaching.
Extraction of gold and silver involves leaching the metal with $CN^{-}$ ion. The metal is recovered by displacement of metal by some other metal from the complex ion.
Hence c is the correct answer.
edited Feb 19