A uniformly tapering vessel of height h whose lower and upper radii are r and R is completely filled with a liquid of density $\mathrm{\rho }$. The forces that acts on the base of the vessel due of the liquid is

• A

  $\pi R^{2}h\rho g$

• B

  ${\mathrm{\pi r}}^2\mathrm{h\rho g}$

• C

  $\mathrm{\pi }{\left(\frac{\mathrm{R}+\mathrm{r}}{2}\right)}^2\mathrm{h\rho g}$

• D

  $\frac{1}{3}\mathrm{\pi }({\mathrm{R}}^2-{\mathrm{r}}^2)\mathrm{h\rho g}$