Which one of the following sets of ions represents a collection of isoelectronic species? (Given: Atomic Number: $F: 9, Cl: 17, Na: 11, Mg: 12, Al: 13, K: 19, Ca: 20, Sc: 21$)

• A
  $Cl^{+}, Na^{+}, Mg^{2+}, Ca^{2+}$
• B
  $Ba^{2+}, Sr^{2+}, K^{+}, Ca^{2+}$
• C
  $N^{3-}, O^{2-}, F^{-}, S^{2-}$
• D
  $K^{+}, Cl^{-}, Ca^{2+}, Sc^{3+}$