A spherical body of diameter Dis falling in viscous medium. 
Its terminal velocity is proportional to : 

• A

  ${\mathrm{D}}^{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.}$

• B

  ${\mathrm{D}}^{\raisebox{1ex}{$3$}\!\left/ \!\raisebox{-1ex}{$2$}\right.}$

• C

  ${\mathrm{D}}^2$

• D

  ${\mathrm{D}}^{\raisebox{1ex}{$5$}\!\left/ \!\raisebox{-1ex}{$2$}\right.}$