If $n, e, \tau$ and $m$ respectively represent the electron density,charge,relaxation time,and mass of the electron,then the resistance of a wire of length $l$ and area of cross-section $A$ will be
- A$\frac{ml}{ne^2 \tau A}$
- B$\frac{m \tau^2 A}{ne^2 l}$
- C$\frac{ne^2 \tau A}{2ml}$
- D$\frac{ne^2 A}{2m \tau l}$
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