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 <em>chemical reaction</em>.
A is <em>wrong</em>. Evaporation is a physical change in which the molecules of the liquid move into the gas phase.
B is <em>wrong</em>. Photosynthesis is the use of sunlight by a plant to convert carbon dioxide and water into glucose.
C is <em>wrong.</em> A physical change does not involve a change to another substance with new chemical properties.
