Answer: C. a substance changes state from solid to liquid
Explanation:
A physical change is one that occurs when the substance of subject changes its form as a result of a reaction. The most noticeable indicator of this is a change in the state of matter such as a change from liquid to solid like the above.
The other options show a chemical change as the form was not changed but its chemical properties such as color was changed or it lost some atoms which became air.
