For the reaction 

${\mathrm{RCH}}_2\mathrm{Br}+{\mathrm{I}}^{-}\stackrel{\text{ Acetone }}{\to }\underset{\text{ major }}{{\mathrm{RCH}}_2}\mathrm{I}+{\mathrm{Br}}^{-}$

The correct statement is 

(A)Transition state is less polar than the localized anion (correct)
(B) The solvent taken is polar aprotic solvent so solvation cannot occur
(C) No,  Br^- cannot act as competing nucleophile as it is precipitated in acetone
(D) No, the above reaction cannot occur in acetic acid.