A bead can slide on a smooth circular wire frame of radius \( R \) which is fixed in a vertical ...

A bead can slide on a smooth circular wire frame of radius \( R \) which is fixed in a vertical plane. The bead is displaced slightly from the highest point of the wire frame. The speed of the bead subsequently as a function of the angle \( \theta \) made by the bead with the vertical line is
(A) \( \sqrt{2 g R} \)
(B) \( \sqrt{2 g R(1-\sin \theta)} \)
(C) \( \sqrt{2 g R(1-\sin \theta)} \)
(D) \( 2 \sqrt{g R} \)