A material of resistivity $\rho$ is formed in the shape of truncated cone of altitude ‘h’ as shown in the fig. the top end has radius ‘a’ while bottom ‘b’. Assuming a uniform current density through any circular cross section of the cone. The resistance between two ends is :

• A

  $\frac{\text{ρh}}{\text{ab}}$

• B

  $\frac{\text{ρh}}{\text{πab}}$

• C

  $\frac{\text{ρa}}{\text{πhb}}$

• D

  $\frac{\text{ρb}}{\text{πah}}$