Find perpendicular distance from the origin to the line joining the points $(\cos \theta, \sin \theta)$ and $(\cos \phi, \sin \phi)$

Question

$\begin {array} {1 1} (A)\;\large\frac{|\sin (\phi- \theta)|}{| \sin \Large\frac{(\phi - \theta)}{2}|} & \quad (B)\;\large\frac{\sin (\phi- \theta)}{ \sin \Large\frac{(\phi - \theta)}{2}} \\ (C)\;\large\frac{|\sin (\phi- \theta)|}{|2 \sin \Large\frac{(\phi - \theta)}{2}|} & \quad (D)\;\large\frac{\sin (\phi- \theta)}{2 \sin \Large\frac{(\phi - \theta)}{2}} \end {array}$