The correct answer is A. Amylase.
Amylase is an enzyme that breaks down starch into smaller molecules called maltose. It is produced in the salivary glands and pancreas. Amylase is the first enzyme to act on starch during digestion. It begins to break down starch into maltose in the mouth, before it is swallowed.
Ptyalin is an enzyme that also breaks down starch, but it is not as effective as amylase. It is produced in the salivary glands and begins to break down starch in the mouth. However, it is not able to break down starch as well as amylase, so most of the starch is not digested until it reaches the stomach.
Pepsin is an enzyme that breaks down proteins. It is produced in the stomach. Pepsin begins to break down proteins in the stomach, but it is not able to break down starch.
Lipase is an enzyme that breaks down lipids. It is produced in the pancreas. Lipase begins to break down lipids in the small intestine.
Therefore, the correct answer is A. Amylase.