A bob of mass M is suspended by a massless string of length L. The horizontal velocity V at position A is just sufficient to make it reach the point B. The angle θ at which the speed of the bob is half of that at A, satisfies
$\theta = \dfrac{\pi}{4}$
$\dfrac{\pi}{4}< \theta < \dfrac{\pi}{2}$
$\dfrac{\pi}{2}< \theta < \dfrac{3\pi}{4}$
$\dfrac{3\pi}{4} < \theta < \pi$