The simplest monosaccharide containing keto group is:

Explanation

Glyceraldehyde: Glyceraldehyde is a monosaccharide with three carbon atoms (a triose sugar). It contains an aldehyde functional group (a carbonyl group with a terminal -CHO). While it is a simple monosaccharide, it does not contain a keto group. Glucose: Glucose is a monosaccharide with six carbon atoms (a hexose sugar). It contains an aldehyde functional group in its linear form, known as an aldohexose. However, in its cyclic form, which is the most stable and prevalent in biological systems, it contains a hydroxyl group (-OH) on its first carbon atom (C1), making it an aldose and not a keto sugar. Dihydroxyacetone: The correct option is dihydroxyacetone. Dihydroxyacetone is the simplest monosaccharide containing a keto group. It is a three-carbon sugar with a ketone functional group (a carbonyl group within the carbon chain) on its central carbon (C2) and hydroxyl groups (-OH) on the other two carbon atoms. Ribose: Ribose is a monosaccharide with five carbon atoms (a pentose sugar). It contains an aldehyde functional group (an aldopentose) on its first carbon atom (C1), making it an aldose and not a keto sugar.In summary, the correct option is c) Dihydroxyacetone. Dihydroxyacetone is the simplest monosaccharide containing a keto group, with a ketone functional group on its central carbon atom.