a
\(\begin{array}{l}
Dimensional\,fomula\,for\,electrical\\
resistivity,\,\rho = \left[ {M{L^3}{T^{ - 3}}{A^{ - 2}}} \right]\\
Dimensional\,formula\,for\,electrical\\
conductivity,\,\sigma = \frac{1}{\rho }\,is\,\left[ {{M^{ - 1}}{L^{ - 3}}{A^2}} \right]
\end{array}\)