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

• Correct answer
  A

  $9.1 \mathrm{\mu J}$
• B

  $4.55 \mathrm{\mu J}$
• C

  $2.3 \mathrm{\mu J}$
• D

  $1.15 \mathrm{\mu J}$

Hence, the correct answer is option: 'A'.