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
  $\frac{ne^2 A}{2m \tau l}$