Which of the following molecules is a simple sugar?

Fructose is classified as a simple sugar, also known as a monosaccharide. It consists of a single sugar unit and is one of the primary sugars found in fruits, honey, and root vegetables. Monosaccharides like fructose serve as basic building blocks for more complex sugars and carbohydrates.

The other molecules listed are examples of disaccharides or polysaccharides. Sucrose, which is composed of glucose and fructose, is a disaccharide. Maltose, formed from two glucose molecules, is also a disaccharide. Starch is a polysaccharide made up of numerous glucose units linked together, functioning as an energy storage form in plants. Therefore, among the options provided, fructose stands out as the only simple sugar.