Which of the following metal ions has a calculated magnetic moment value of$\begin{array}{ll}\sqrt{24}& \text{ B.M.) }\end{array}$

$\begin{array}{l}{\mathrm{Mn}}^{+2}-\left[\mathrm{Ar}\right]4{ \mathrm{s}}^{0}3{ \mathrm{d}}^5-5 \mathrm{unpaired} {\mathrm{e}}^{-}, \mathrm{i}.\mathrm{e}. \mathrm{n}=5\\ {\mathrm{Fe}}^{+2}-\left[\mathrm{Ar}\right]4{ \mathrm{s}}^{0}3{ \mathrm{d}}^6-\mathrm{n}=4{\mathrm{e}}^{-}\to \mathrm{\mu }=\sqrt{4(4+2)}=\sqrt{24}\mathrm{BM}\\ {\mathrm{Fe}}^{+3}-\left[\mathrm{Ar}\right]4{ \mathrm{s}}^{0}3{ \mathrm{d}}^5-\mathrm{n}=5{\mathrm{e}}^{-}\\ {\mathrm{Co}}^{+2}-{\mathrm{Co}}^{+2}-\left[\mathrm{Ar}\right]4{ \mathrm{s}}^{0}3{ \mathrm{d}}^7-\mathrm{n}=3{\mathrm{e}}^{-}\end{array}$

Hence, the correct option is ( B)