An aqueous solution of $\left[\mathrm{Mn}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}$ complex is pale pink in colour. The probable reasons for it are
\[ \begin{array}{l} \text{(A) Presence of } { }^{6}\mathrm{A}_{1}\mathrm{g} \text{ ground state} \\ \text{(B) Disallowed transition by spin selection rule} \\ \text{(C) Presence of } { }^{2}\mathrm{T}_{2}\mathrm{g} \text{ ground state} \\ \text{(D) Charge transfer transition} \end{array} \]