The bob of simple pendulum having length l, is displaced from mean position to an angular position $\theta$ with respect to vertical. If it is released, then velocity of bob at lowest position :

Question

( A ) $\sqrt{2gl}$
( B ) $\sqrt{2gl(1-\cos\theta)}$
( C ) $\sqrt{2gl\cos\theta}$
( D ) $\sqrt{2gl(1+\cos\theta)}$