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 $(iv)$