Two life preservers have identical volumes, but one is filled with Styrofoam while the other is filled with sand. When the two life preservers are worn by swimmers, one swimmer floats with part of the preserver above water, and the other swimmer sinks. In this case the buoyant force is greater on the life preserver filled with:.
A) Styrofoam.
B) Sand.
C) Same on each as long as their volumes are the same.