c
\(\begin{array}{l}
{\rm{Dimensions of}}\,\mu = \left[ {ML{T^{ - 2}}{A^{ - 2}}} \right]\\
{\rm{Dimensions of}}\, \in \, = \,\left[ {{M^{ - 1}}{L^{ - 3}}{T^4}{A^2}} \right]\\
{\rm{Dimensions of}}\,R\, = \left[ {M{L^2}{T^{ - 3}}{A^{ - 2}}} \right]\\
\therefore \frac{{{\rm{Dimensions of}}\,\mu }}{{{\rm{Dimensions of}}\, \in }} = \left[ {\frac{{ML{T^{ - 2}}{A^{ - 2}}}}{{{M^{ - 1}}{L^{ - 3}}{T^4}{A^2}}}} \right]\\
= \left[ {{M^2}{L^4}{T^6}{A^{ - 4}}} \right] = \left[ {{R^2}} \right]
\end{array}\)