$A$ closely wound solenoid of $800$ turns and area of cross section $2.5 \times 10^{-4} \;m^{2}$ carries a current of $3.0 \;A$. If the solenoid is free to turn about the vertical direction and a uniform horizontal magnetic field of $0.25 \;T$ is applied,what is the magnitude of torque on the solenoid when its axis makes an angle of $30^{\circ}$ with the direction of the applied field?

• A
  $7.5 \times 10^{-2} \;N \,m$
• B
  $2.5 \times 10^{-2} \;N \,m$
• C
  $6.5 \times 10^{-3} \;N \,m$
• D
  $1.25 \times 10^{-2} \;N \,m$