In some forms of spectroscopy, it is necessary to determine whether ions are isoelectronic. This means that they have the same number of electrons. Which ion is not isoelectronic with $\text{K}^+$?
- A$\text{Ca}^{2+}$
- B$\text{Cl}^-$
- C$\text{S}^{2-}$
- D$\text{Ti}^{3+}$