Among statements $(a)-(d),$ the correct ones are
$(a)$ Limestone is decomposed to $CaO$ during the extraction of iron from its oxides.
$(b)$ In the extraction of silver,silver is extracted as an anionic complex.
$(c)$ Nickel is purified by Mond's process.
$(d)$ $Zr$ and $Ti$ are purified by Van Arkel method.

• A
  $(a)$ and $(b)$ only
• B
  $(b), (c)$ and $(d)$ only
• C
  $(a), (c)$ and $(d)$ only
• D
  $(a), (b), (c)$ and $(d)$