If you want to consider that the question undeniably states "the ball is blue", then it can't be more n than it is blue, since we've already assigned it 100% blueness.
The fact that the ball is made of plastic is not really relevant to anything.
Unless you explain where you get the link between the colour of the ball and the material it is made from, that makes no sense.
They don't actually need to do that, because it won't prove either side of the discussion.