Among the following, the set of isoelectronic ions is

• A

  $\mathrm{Na}^{+}, \mathrm{Mg}^{2+}, \mathrm{F}^{-}, \mathrm{Cl}^{-}$
• B

  $\mathrm{Na}^{+}, \mathrm{Ca}^{2+}, \mathrm{F}^{-}, \mathrm{O}^{2-}$
• Correct answer
  C

  $\mathrm{Na}^{+}, \mathrm{Mg}^{2+}, \mathrm{F}^{-}, \mathrm{O}^{2-}$
• D

  $\mathrm{Na}^{+}, \mathrm{K}^{+}, \mathrm{S}^{2-}, \mathrm{Cl}$

Hence, the correct answer is option: 'C'.