The radius of the bore of a capillary tube is r and the angle of contact of the liquid is $\theta$. When the tube is dipped in the liquid, the radius of curvature of the
meniscus of liquid rising in the tube is

• A

  $\mathrm{rsin}\mathrm{\theta }$

• B

  $\mathrm{r}/\sin \mathrm{\theta }$

• C

  $\mathrm{rcos}\mathrm{\theta }$

• D

  $\mathrm{r}/\cos \mathrm{\theta }$