Which one of the following polymers does not contain glucose units?

Which one of the following polymers does not contain glucose units?

Glycogen
Starch
Cellulose
Rubber
This question was previously asked in
UPSC CDS-2 – 2017
The correct answer is Rubber.
Glycogen, Starch, and Cellulose are all polysaccharides, which are complex carbohydrates. They are polymers made up of repeating units of glucose (a monosaccharide). Glycogen is the storage form of glucose in animals and fungi. Starch is the storage form of glucose in plants. Cellulose is a major structural component of plant cell walls. Natural rubber is a polymer of isoprene (2-methyl-1,3-butadiene), which is an organic compound belonging to the diene class.
While glycogen, starch, and cellulose are polymers of glucose, they differ in the type of glycosidic bonds connecting the glucose units and their branching structures, which gives them different properties and functions. Rubber’s monomer unit is chemically distinct from glucose.