The Answer has no logic. If you pull the plug then notice the water has nowhere to go(the tub isn't connected to the plumbing system because its off the ground also, ponies aren't able to grasp chains). The bucket will either not fit or won't be able to get all the water out because of the shape(you can't empty all of the liquid from a rectangular container with a bucket, I've tried). The spoon would take way to long. The cup may have the shape problem as the bucket unless the tub has the same curvature as the cup but, even then it would take a long time. The only answer that remotely might be logical is flipping over the tub but, that would make a mess on the floor.