Smoke is an example of:

Smoke is produced when materials burn, such as wood or coal. During burning, not all material is completely burned, and tiny solid particles like soot or ash are released into the air. Air is a mixture of gases, primarily nitrogen and oxygen.

Therefore, smoke consists of solid particles suspended in a gas. This means it is a dispersion where the solid is the dispersed phase and the gas is the dispersion medium.

Now, examining the options:

Option A: Solid dispersed in solid. This describes mixtures like alloys or composites, where both phases are solid. Smoke does not fit this, as it involves gas.

Option B: Gas dispersed in liquid. This describes systems like carbonated drinks, where gas bubbles are dispersed in a liquid. Smoke is not a liquid-based system.

Option C: Solid dispersed in gas. This matches smoke, as solid particles are dispersed in a gaseous medium like air.

Option D: Gas dispersed in solid. This describes materials like pumice or foam, where gas pockets are trapped within a solid. Smoke does not have a solid continuous phase.

Hence, smoke is an example of solid dispersed in gas.

Hence, the correct answer is Option C.