Answer:
C) The color changes and the release of energy indicate a chemical reaction.
Step-by-step explanation:
The color changes in the fireworks when they start to burn is derived form the different compounds that are being burnt, for example strontium carbonate when is burnt it burns in a red color, barium chloride is colored green when is burnt but that is why it is a chemical reaction, because of the added energy and the color that it expells.