A sample of food containing one type of a large molecule was treated with a specific digestive enzyme. Nutrient tests performed on the resulting products showed the presence of simple sugars, only. Based on these test results, the original large molecules contained in the sample were molecules of

protein

glucose

starch

DNA

The best answer is starch.

Starch is a type of carbohydrate.

Carbohydrates are made of simple sugars, namely glucose. A simple sugar is a single molecule of a sugar. A single sugar molecule is called a monomer.

Starch is made of many monomers or units of glucose linked together and is thus called a polysaccharide. When it is broken down, the result is its many glucose units are separated from each other by breaking the chemical bonds that hold them together, and are thus released as simple sugars.