8. How docs glucose 6-phosphate turn on the activity of glycogen synthase? (A) Glucose 6-phosphate can directly activate glycogen synthase via an allosteric regulation. (B) Glucose 6-phosphate can inhibit phosphorylase kinase, leading to giycogen synthase activation. (C) Glucose 6-phosphate is an inducer to turn on glycogen synthase kinase for activation of glycogen synthase. (D) Gluco se 6-phosphate can activate glycogen synthase via phosphorylation by a G6P-dependent kinase. (E) Glucose 6-phosphate can activate phosphoprotein phosphatase-1 for glycogen synthase activation.