The correct option is A Fructose
Fructose is a hexose monosaccharide. It is the sweetest of all naturally occurring sugars because its sweetness index is very high.
Lactose is a disaccharide which is made up of galactose and glucose units joined together by a glycosidic bond. It is also known as milk sugar because it is found in milk. It can be broken down into galactose and glucose in the presence of enzyme lactase.
Ribose is a pentose monosaccharide found in the RNA.
Maltose is a disaccharide which is made up of 2 glucose units joined together by a glycosidic bond. It is also known as malt sugar and is found in cereals like barley, from which maltose syrup is obtained.