A. Enzymes break up glycogen from its non-reducing end one glucose at a time.
Explanation:
Glycogen is a polysaccharide made up of glucose moieties and serves as energy stores in animals, bacteria and also fungi.
Glycogen is degraded or broken down by an enzyme called glycogen phosphorylase. Glycogen phosphorylase hydrolyses glycogen to produce glucose-1-phosphate and glycogen molecule short of one glucose. This enzyme only catalyzes from the non reducing end of a glycogen where terminal carbon is free of ketone or aldehyde group.