Which of the following shall have the highest value of magnetic moment?

(a) Valence shell electron configuration of $\mathrm{Zn}\left(\mathrm{II}\right)\text{\hspace{0.33em}is\hspace{0.33em}}3{\mathrm{d}}^{10}4{\mathrm{s}}^0$. So has no unpaired electrons.
(b) Valence shell electron configuration of $\mathrm{Mn}\left(\mathrm{IV}\right)\text{\hspace{0.33em}is\hspace{0.33em}}3{\mathrm{d}}^{3}4{\mathrm{s}}^0$. So has 3 unpaired electrons.

(c) Valence shell electron configuration of $\mathrm{Fe}\left(\mathrm{II}\right)\text{\hspace{0.33em}is\hspace{0.33em}}3{\mathrm{d}}^{6}4{\mathrm{s}}^0$. So has 4 unpaired electrons.
(d) Valence shell electron configuration of $\mathrm{Ti}\left(\mathrm{III}\right)\text{\hspace{0.33em}is\hspace{0.33em}}3{\mathrm{d}}^{1}4{\mathrm{s}}^0$. So has one unpaired electrons.
So, Fe(Il) has highest value of magnetic moment as given by B. M.