$\begin{array}{1 1} \text{a.Ions made of 3 types of atom that act as 2 ions} \\ \text{
b. Ions that have 2 or more atoms} \\ \text{
c. Ions that are made of more than 1 type of atom and act as one} \\ \text{
d. Ions that have 5 different types of atoms}
\end{array} $
