A short bar magnet is placed in the magnetic meridian of the earth with north pole pointing north. Neutral points are found at a distance of $30\;cm$ from the magnet on the East - west line, drawn through the middle point of the magnet. The magnetic moment of the magnet in $Am^2$ is close to :

Question

$\begin{array}{1 1} 9.7 \\ 4.9 \\ 19.4 \\ 14.6 \end{array}$