Which of the following is NOT a monosaccharide?

Sucrose is classified as a disaccharide, which is a type of carbohydrate composed of two monosaccharide units bonded together. In contrast, glucose, fructose, and galactose are all monosaccharides; they are the simplest form of carbohydrates that cannot be hydrolyzed into smaller sugars. Monosaccharides, such as glucose and fructose, consist of single sugar molecules that serve as the building blocks for more complex carbohydrates. Since sucrose is formed from the combination of glucose and fructose through a glycosidic bond, it does not fit the definition of a monosaccharide. Recognizing the structural differences and the criteria for classification of sugars is essential in understanding carbohydrate metabolism and nutrition.