Cellulose, the most important constituent of plant cell wall is made up of

[A] branched chain of glucose molecules linked by (3-1, 4 glycosidic bond in straight chain and a-1, 6 glycosidic bond at the site of branching

[B] unbranched chain of glucose molecules linked by (3-1, 4 glycosidic bond

[C] branched chain of glucose molecules linked by a-1, 6 glycosidic bond at the site of branching

[D] unbranched chain of glucose molecules linked by a-1, 4 glycosidic bond