In a region of space the electric field is in the x-direction and proportional to x, i.e., $\overrightarrow{\mathrm{E}}={\mathrm{E}}_0\mathrm{x}\hat{\mathrm{i}}$. Consider an imaginary cubical volume of edge a with its edges parallel to the axes of coordinates. The charge inside this volume will be

• A

  zero

• B

  ${\mathrm{\epsilon }}_0{\mathrm{E}}_0{\mathrm{a}}^3$

• C

  $\frac{1}{{\mathrm{\epsilon }}_0}{\mathrm{E}}_0{\mathrm{a}}^3$

• D

  $\frac{1}{6}{\mathrm{\epsilon }}_0{\mathrm{E}}_0{\mathrm{a}}^3$