Which compound forms a colourless solution when dissolved in ${\mathrm{H}}_2\mathrm{O}$ ?

${\mathrm{ZnCl}}_2$ compound forms a colourless solution when dissolved in  ${\mathrm{H}}_2\mathrm{O}$. Because no visible light is absorbed, there are no openings for an electron to be promoted into the zinc ion. Since the third level is all occupied. Complexes of zinc are also colourless. Hence, option D is correct.