Final answer:
Starch is the plant form of the polysaccharide in option D, starch, and it serves as a storage form of energy in plants. Glycogen serves the same function in animals, while cellulose is the structural component of cell walls in plants.
Step-by-step explanation:
Starch is the plant form of the polysaccharide found in option D) Starch. Starch is a storage form of energy in plants and is made up of glucose monomers. It is stored in different parts of the plant like roots and seeds. Glycogen, on the other hand, is the storage form of energy in animals, while cellulose is the structural component of cell walls in green plants.