Following complete hydrolysis of a sample of glycogen and a sample of cellulose, which statement must be TRUE?

A) The glycogen sample is more soluble than the cellulose sample.
B) The cellulose sample is more soluble than the glycogen sample.
C) Both samples consist of a mixture of $\alpha$ -D-glucose and $\beta$ -D-glucose.
D) The glycogen sample has a higher ratio of $\alpha$ -D-glucose than the cellulose sample.
E) The cellulose sample contains only $\beta$ -D-glucose.