9.9. Which of the following concerning xylitol is false?

A、itisapolyhydroxyalcohol-asugarsubstitute,nutritivesweetener.
B、itreducesthelevelofcariogenicmicroorganismsintheoralcavity.
C、itcanbefermentedbyoralmicroorganisms.
D、ithasanticarieseffect.
E、itmayhavealaxativeeffect.