Electronic charge $'e'= \large\frac{\text{Dipole moment}}{\text{Bond length}}$
$\qquad= \large\frac{1.2 \times 10^{-18}\;esu cm}{1.0 \times 10^{-8} \;cm}$
$\qquad =1.2 \times 10^{-10}\;esu$
Thus, fraction of electronic charge on each end
$\qquad=\large\frac{1.2 \times 10^{-10}}{4.8 \times 10^{-10}}$$=0.25$
$\qquad =25 \% $of $'e'$
Hence A is the correct answer.