$A$ wire carrying current $I$ is tied between points $P$ and $Q$ and is in the shape of a circular arc of radius $R$ due to a uniform magnetic field $B$ (perpendicular to the plane of the paper,shown by $\times \times \times $) in the vicinity of the wire. If the wire subtends an angle $2\theta_0$ at the centre of the circle (of which it forms an arc),then the tension in the wire is:

• A
  $\frac{IBR}{2 \sin \theta_0}$
• B
  $\frac{IBR \theta_0}{\sin \theta_0}$
• C
  $IBR$
• D
  $\frac{IBR}{\sin \theta_0}$