Natural selection. Have you heard of his finch studies? That will help you to understand natural selection if you need help.
Enzymes are made of strings of amino acids chemically bonded to one another. These bonds give each enzyme a unique structure, which determines its function. They mostly break down carbohydrates and fats. Once a protein source reaches your stomach, hydrochloric acid and enzymes called proteases break it down into smaller chains of amino acids. Amino acids are joined together by peptides, which are broken by proteases.
All of these are accurate
I would say that the most likely answer is C.
While B and D could happen that are too vague and non-descript, A is completely wrong.