Jeffry was wondering why when he made breakfast, that after he was done cooking, the mass of everything he used was not the same. What best describes why this is so, according to the law of conservation of mass.

A: cooking causes water vapor to escape so it cannot be added to the mass
B: cooking makes things solid and that adds to the mass
C: cooking changes the matter so it is different

D: cooking did nothing so he measured the mass wrong