The ionic radii of $Rb^{+}$ and $I^{-}$ are $1.46 \ \mathring{A}$ and $2.16 \ \mathring{A}$,respectively. The most probable type of structure exhibited by it is:

• A
  $CsCl$ type
• B
  $ZnS$ type
• C
  $NaCl$ type
• D
  $CaF_2$ type