The radius R of the soap , bubble is doubled under isothermal condition. If T be the surface tension of soap bubble, the required surface energy ln doing so is given by :

• A

  $32{\mathrm{\pi R}}^2\mathrm{T}$

• B

  $24{\mathrm{\pi R}}^2\mathrm{T}$

• C

  $8 {\mathrm{\pi R}}^2\mathrm{T}$

• D

  $4 {\mathrm{\pi R}}^2\mathrm{T}$