A capillary tube of radius r is dipped in a liquid of density $\rho$ and surface tension S. If the angle of contact is $\theta$, the pressure difference between the two surfaces in the beaker and the capillary

• A

  $\frac{S}{r}\cos \theta$

• B

  $\frac{2S}{r}\cos \theta$

• C

  $\frac{S}{r\cos \theta }$

• D

  $\frac{2S}{r\cos \theta }$