(a) From $F = \frac{1}{4\pi\varepsilon_{0}\ }\begin{array}{r}
\ \\
\
\end{array}\frac{q_{1}q_{2}}{r^{2}}$
$\varepsilon_{0} = \frac{1}{4\pi F\ }\begin{array}{r}
\ \\
\
\end{array}\frac{q_{1}q_{2}}{r^{2}} = \frac{\left\lbrack A^{2}T^{2} \right\rbrack}{\left\lbrack MLT^{- 2} \right\rbrack\left\lbrack L^{2} \right\rbrack}$
$= \lbrack M^{- 1}L^{- 3}T^{4}A^{2}\rbrack$