Which of the following aquated metal ions has the highest paramagnerism?

$\begin{array}{r}{\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}\to 3\text{ unpaired electrons. }\\ {\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}\to 4\text{ unpaired electrons. }\\ {\left[\mathrm{Cu}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}\to 1\text{ unpaired electron. }\\ {\left[\mathrm{Zn}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}\to 0\text{ unpaired electron. }\end{array}$