Answer:
C. solid
Step-by-step explanation:
Solid is a hard and not able to flow; not like a liquid or gas. Having no holes; not hollow. Something that is not liquid and gas. Solid has fixed volume but not a fixed shape.
The liquid is something that flows freely; a substance that is not solid or gas.
Gas is a substance that neither liquid nor solid, e.g. air.
Plasma is an electrically neutral ionized gas in an electric discharge; distinctly different from solids and liquids and normal gases.
Therefore, the correct answer is C. solid.