Number of complexes from the following with even number of unpaired "d" electrons is ____. [ V ( H_2 O )_6]^3+,[ Cr ( H_2 O )_6]^2+,[ Fe ( H_2 O…

Number of complexes from the following with even number of unpaired "d" electrons is $\displaystyle \_\_\_\_$. $$\left[\mathrm{V}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+},\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+},\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+},\left[\mathrm{Ni}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+},\left[\mathrm{Cu}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+} $$ [Given atomic numbers : $\displaystyle \mathrm{V}=23, \mathrm{Cr}=24, \mathrm{Fe}=26, \mathrm{Ni}=28 \mathrm{Cu}=29$ ]