The correct option is B Monosaccharide
Nucleotide which is the structural component of genetic materials, is composed of three chemically distinct components. One is a nitrogenous base, the second is deoxyribose sugar if it is a DNA and ribose sugar if it is an RNA; and the third, a phosphate group. Ribose and deoxyribose are monosaccharides because they are made up of simple units of carbohydrates.