In a tangent galvanometer , When a current of $10\;mA$ is passed the deflection is $31^{\circ}$ By what percentage , the current has to be increased , so as to produce a deflection of $42^{\circ}$?

Question

$\begin{array}{1 1} 25\% \\ 30\% \\ 50\% \\ 75\% \end{array} $