Select the correct statement :

Because the number of unpaired electrons in ferrocyanide and ferricyanide differs, they can be distinguished by the solid-state magnetic moment.

$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\mathrm{Br}\right]{\mathrm{SO}}_4$ produces white precipitate of ${\mathrm{BaSO}}_4$ with ${\mathrm{BaCl}}_2\text{ (aq.) }$Whereas

${\left[{\mathrm{CoCNH}}_3\right)}_5{\mathrm{SO}}_4$ produces yellow precipitate of ${\mathrm{BaSO}}_4$. Br do not.

$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\mathrm{Br}\right]\mathrm{Cl}$ gives white precipitate with ${\mathrm{AgNO}}_3$, whereas

$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\mathrm{Cl}\right]\mathrm{Br}$ does not.

Thus, the correct option is D.