The correct answer is option B, that is, digestion of food.
Digestion of food in the body is a decomposition reaction, it is a kind of chemical reaction in which single compound dissociates into two or more basic components. In the process of digestion, proteins, carbohydrates, and fats dissociate to basic constituents, which provide energy to function.
Digestion of food is regarded as chemical change as different chemical reactions occur at the time of food digestion.