Which of the following compounds have colour but no unpaired electrons?

${\mathrm{KMnO}}_4$ is coloured due to an electronic transition, which is not a d-d transition because the Mn in this combination lacks d-electrons. It results from a charge transfer process within the molecule in which an electron from the highest energy molecular orbital in one of the $\mathrm{Mn}-\mathrm{O}$linkages is moved to an empty d orbital on the manganese. This stimulus has the same energy as a yellow photon, therefore yellow light is absorbed, leaving us with purple, the complimentary colour.
As a result, it is an example of Ligand to Metal Charge Transfer.

Hence, option A is correct.