must be solid. could be either solid or liquid. must be liquid. could be either liquid or gas.
I gave my students this multiple choice question: A sample in a cylindrical container has a cylindrical shape and a fixed volume. The state of matter of the sample

Only one answer is correct among these 4 choices:
- must be solid.
- could be either solid or liquid.
- must be liquid.
- could be either liquid or gas.

Could you tell me which one is correct?

could be either solid or liquid.