Final answer:
A charge distribution uniformly spread throughout the volume of a solid conducting sphere is unstable because the charges will move to the surface due to electrostatic forces.
Step-by-step explanation:
The question pertains to the stability of a charge distribution in a solid conducting sphere when uniformly spread throughout its volume. In electrostatics, a conductor in equilibrium will have charges residing on its surface, not within its volume. Therefore, this scenario, though hypothetical, would be an unstable configuration.
Realistically, any excess charge placed within a conductor will move to the surface, making the inner charge density zero and causing the surface to have a uniform charge density. This is due to the electrostatic repulsion between charges and the principle of charge relaxation in conductors. Hence, the correct answer here would be (b) Unstable, since a uniform volume distribution of charge in a conductor cannot be sustained.