Answer:
D. A chemical reaction
Explanation:
The evolution of a gas and the formation of a new solid with different properties are signs that the original materials have changed into something else.
They have been in a chemical reaction.
A is wrong. Evaporation is a physical change in which the molecules of the liquid move into the gas phase.
B is wrong. Photosynthesis is the use of sunlight by a plant to convert carbon dioxide and water into glucose.
C is wrong. A physical change does not involve a change to another substance with new chemical properties.