Why Does Fluoride Treatment Render Teeth More Resistant to Decay

Why does fluoride treatment render teeth more resistant to decay?

A) Fluoride kills the bacteria in the mouth that make the acids that decay teeth.
B) Fluoride stimulates production of tooth enamel to replace that lost to decay.
C) Fluoride reduces saliva production, keeping teeth drier and thus reducing decay.
D) Fluoride converts hydroxyapatite to fluoroapatite that is less reactive with acids.
E) Fluoride dissolves plaque, reducing its decaying contact with teeth.