David is making an omelet. She breaks some eggs into a bowl and uses a fork to beat the eggs. Then, she mixes shredded cheese into the eggs. Finally, she pours the mixture into a hot pan and cooks it until it forms a solid omelet. During which step does a chemical change occur? (7 Points) David breaks eggs into a bowl.

David uses a fork to beat the eggs.

David makes a mixture of eggs and cheese.

David cooks the mixture of eggs and cheese until it forms a solid.