Our bodies do not make starch, but we often eat plant foods which contain starch which we digest into the building block that is used to make starch.

The correct answer is glucose. 

Glucose is the major carbohydrate that can be absorbed and used by humans for energy. In animals, glucose is stored as glycogen in the liver and the muscle tissue in contrast to plants wherein they store glucose as amylose and amylopectin (also known as starch). In digestion of starch, it will start with the saliva where the enzyme salivary amylase will break it down to smaller molecules of starch and limit dextrins. These will be further broken down in the intestines using the pancreatic amylase forming di and trisaccharides. These di and trisaccharides will be metabolized by brush border enzyme to eventually produce glucose (and other monosaccharides that can be absorbed such as fructose and galactose).

The answer would be sand and gravel