An electron enters the space between the plates of a charged capacitor as shown. The surface charge density on the plates is $\sigma$. The electric field intensity in the space between the plates is $E$. $A$ uniform magnetic field $B$ also exists in the space,perpendicular to the direction of $E$. The electron moves perpendicular to both $\overrightarrow{E}$ and $\overrightarrow{B}$ without any change in direction. The time taken by the electron to travel a distance $l$ in the space is:

• A
  $\frac{\sigma l}{\varepsilon_{0} B}$
• B
  $\frac{\sigma B}{\varepsilon_{0} l}$
• C
  $\frac{\varepsilon_{0} l B}{\sigma}$
• D
  $\frac{\varepsilon_{0} l}{\sigma B}$