A small wooden ball, an oil drop and an air bubble each of radius r are moving up in a liquid of viscosity $\mathrm{\eta }$. The terminal velocities of these three, i.e., ${\mathrm{v}}_{\mathrm{w}},{\mathrm{v}}_{\mathrm{o}} \mathrm{and} {\mathrm{v}}_{\mathrm{a}}$ 
respectively will be such that:

• A

  ${\mathrm{V}}_{\mathrm{w}}={\mathrm{v}}_{\mathrm{o}}= {\mathrm{v}}_{\mathrm{a}}$

• B

  ${\mathrm{V}}_{\mathrm{w}}<{\mathrm{v}}_{\mathrm{o}}<{\mathrm{v}}_{\mathrm{a}}$

• C

  ${\mathrm{V}}_{\mathrm{w}}>{\mathrm{v}}_{\mathrm{o}}>{\mathrm{v}}_{\mathrm{a}}$

• D

  ${\mathrm{V}}_{\mathrm{w}}>{\mathrm{v}}_{\mathrm{a}}>{\mathrm{v}}_{\mathrm{o}}$