Question

a polysaccharide is a type of polymer. polymers are molecules made of many—often hundreds or thousands—of repeating units called monomers. in polysaccharides, the monomers are simple sugars like glucose, fructose, or galactose. some polysaccharides have only one type of monomer, while other polysaccharides have two or more different types of monomers.
select the polysaccharide.

Explanation:

A polysaccharide is a polymer made of many monomer (simple sugar) units. The first structure is a disaccharide (two - sugar unit). The second structure is a monosaccharide. The third structure has multiple sugar units linked together, which fits the definition of a polysaccharide as it has more than two sugar (monomer) units.

Answer:

The third structure (the one with multiple sugar - unit linkages) is the polysaccharide.