B, the hollow sphere, as it has the lowest mass to surface area ratio (surface area in the plane perpendicular to the direction of motion) compared to the others, meaning air resistance affects it more (assuming there is air) and it has a lower terminal velocity too. However, you cannot actually work it out properly unless you know the thickness of the ring/disk, and the mass of all of the objects. I just made up values for masses and SA that seemed reasonable.