Water rises in a capillary tube to a certain height such that the upward force due to surface tension is balanced by 75 x 10- a N force due to the weight of the liquid. If the surface tension of water is $\widehat{6}\times {10}^{-2}{\mathrm{Nm}}^{-1}$, the inner circumference of the capillary must be

• A

  $1\cdot 25\times {10}^{-2}\mathrm{m}$

• B

  $0\cdot 50\times {10}^{-2}m$

• C

  $6\cdot 5\times {10}^{-2}m$

• D

  $12\cdot 5\times {10}^{-2}m$