At $25^oC$ molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is $9.54 \; ohm^{-1} cm^2 mol^{-1}$ and at infinite dilution its molar conductance is $238 \; ohm^{-1} cm^2 mol^{-1}$. The degree of ionisation of ammonium hydroxide at the same concentration and temperature is -

Question

( A ) $20.800 \%$
( B ) $4.008 \%$
( C ) $40.800 \%$
( D ) $2.080 \%$