From argentite $(Ag_2S)$ ore,the method used in obtaining metallic silver is:

• A
  Fused mixture of $Ag_2S$ and $KCl$ is electrolysed
• B
  $Ag_2S$ is reduced with $CO$
• C
  $Ag_2S$ is roasted to $Ag_2O$ which is reduced with carbon
• D
  Treating argentite with $NaCN$ solution followed by metal displacement with zinc