The answer is letter B. enzymes.
Digestive enzymes are the ones responsible in breaking down macromolecules into tiny and manageable pieces that can be easily processed by the digestive system. They play a crucial role in facilitating the absorption of nutrients within the body and can be found within the digestive tracts of animals and humans. In the stomach, it is secreted by the lining of the stomach which in turn produces juices that are necessary to break down the food before it passes through the intestines.