The answer is C. The toasting of the marshmallow is a chemical change.
Why?
Based on the other options:
A.) The melting of the chocolate ISNT a chemical change. It's a physical change.
B.) The digestion of food is NOT a physical change. It's a chemical change.
D. The burning of the wood for the campfire is NOT a physical change. It's a chemical change.
Physical Change: Doesn’t change the composition of the matter. However, its physical appearance and properties can change.
Chemical Change: During chemical changes, the matter that you start with isn’t the matter you end up with.