{{B}}quEstions 16 to 20 ArE BAsED on thE Following tAlk.{{/B}}

A、BECAusE pAtiEnts mAy not BE ABlE to AFForD thE $ 300 priCE tAg.
B、BECAusE it CAnnot stop thE grinDing or ClEnChing.
C、BECAusE it CAnnot protECt thE tEEth.
D、BECAusE it will DAmAgE thE ArrAngEmEnt oF thE tEEth.