Answer: Option (c) is the correct answer.
Step-by-step explanation:
A change that does not bring any difference in chemical composition of a substance are known as physical properties.
For example, shape, size, mass, volume, density, etc of a substance are all physical change.
And, a change in which there occurs a difference in chemical composition of a substance then it is known as chemical change.
For example, precipitation, reactivity, toxicity etc are chemical change.
Fireworks exploding is a chemical change.
Thus, we can conclude that out of the given options fireworks exploding represents a chemical change.