Thermal Expansion: Two Steel Spheres Are Made of the Same

Thermal expansion: Two steel spheres are made of the same material and have the same diameter, but one is solid and the other is hollow. If their temperature is increased by the same amount,

A) the solid sphere becomes bigger than the hollow one.
B) the hollow sphere becomes bigger than the solid one.
C) the two spheres remain of equal size.
D) the solid sphere becomes heavier and the hollow one becomes lighter.
E) the solid sphere becomes lighter and the hollow one becomes heavier.