Since air resistance is being ignored, there is no force in the horizontal direction. Therefore, the -component of the particle's velocity is constant. We are told that the stone is thrown in the direction. Therefore, the -component of the velocity must be positive. Therefore, graph II represents versus . The -component of the particle's velocity vector is initially positive, but it decreases at a constant rate due to the force of gravity, and eventually becomes negative. Therefore, graph III represents versus . Therefore, answer (C) is correct.