The color of KMnO4 is due to:

Explanation:

The colour of KMnO4 is due to the ligand to metal charge transfer.

The magnesium (Mn) metal is in its highest Oxidation State i.e +7 and it has no electron in its outermost shell The electronic configuration is [Ar]3d⁰4s⁰ hence there is no possibility of d-d transition.

There is transfer of charge takes place from the 2p orbital of oxygen ligand (O^2-) to the vacant orbital of Mn atom and we get intense purple colour of this compound.

Final Answer:

 the correct option is [c] L → M charge transfer transition