d
(d) In the above question for calculating equivalent resistance between two opposite square faces.
$l = 100 \,cm = 1\,m$, $A = 1\,cm^2 = 10^{-4} \,m^2$, so resistance $R = 3 \times 10^{-7} \times \frac{1}{{{{10}^{ - 4}}}}= 3 \times 10^{-3} \,\Omega $