If $n, e, \tau$ and $m$ are representing electron density, charge, relaxation time and mass of an electron respectively, then the resistance of a wire of length / and cross-sectional area $A$ is given by
A$\frac{m l}{n e^2 \tau A}$
B$\frac{m \tau A}{n e^2 I}$
C$\frac{n e^2 \tau A}{m l}$
D$\frac{n e^2 A}{m \tau I}$
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A$\frac{m l}{n e^2 \tau A}$
a (a)
$R=\frac{\rho l}{A}$
$R=\frac{m l}{n e^2 I A}$
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