So, based from your options, I believe that the best option that would make the most sense in this case would be of that on how the material inside the earth's mantel would rise up, but, it would also not sink. So, basically,it rises, and it wont sink, it goes up and down, which in this case, it's a good thing and it's also pretty neat to see this.
So, based from your options listed above, your correct answer to this question would be of that (<span>Rises up but does not sink down)