A 250 N turn rectangular coil of length $2.1\;cm$ and width $1.25\;cm$ carries a current of $85 \mu A$ and subjected to magnetic field of strength $0.85\;T$ Work done for rotating the coil by $180^{\circ}$ against the torque is :

Question

$\begin{array}{1 1} (1) 9.1 \mu J \\ (2) 4.55\;\mu\;J \\ (3) 2.3 \;\mu \;J \\ (4) 1.15\;\mu\;J \end{array}$