\[\begin {array} {1 1} (a)\;2 \pi \times 10^{-2} Nm & \quad (b)\;2.5 \pi \times 10^{-2} \;Nm \\ (c)\;4 \pi \times 10^{-2} Nm & \quad (d)\;4.5 \pi \times 10^{-2} Nm \end {array}\]