Which of the following species are isoelectronic species? $(i)$ $O^{2-}$, $(ii)$ $F^{-}$, $(iii)$ $Na^{+}$, $(iv)$ $Mg^{2+}$

• A
  $(i)$, $(ii)$ and $(iii)$ only
• B
  $(i)$, $(iii)$ and $(iv)$ only
• C
  $(iii)$ and $(iv)$ only
• D
  $(i)$, $(ii)$, $(iii)$ and $(iv)$