Strong yellow colour of' ${\mathrm{Ce}}^{4+}$ solutions and blood red colour of ${\mathrm{Sm}}^{2+}$ solution arises due to :

Strong yellow colour of' ${\mathrm{Ce}}^{4+}$ solutions and blood red colour of ${\mathrm{Sm}}^{2+}$ solution arises due to charge transfer from L to M

Intense colours are observed because of charge transfer spectra