Adenylyl cyclase catalyzes the synthesis of cAMP, and cAMP hydrolysis is catalyzed by a 5'-phosphodiesterase. If caffeine inhibits 5'-phosphodiesterases, drinking a caffeinated beverage would ____ cAMP levels and ____ glycogen phosphorylase activity.
A) increase; decrease B) increase; increase C) decrease; decrease D) decrease; increase E) have no effect; have no effect