In a region of space the electric field in the `x`-direction and proportional to `x`i.e., `vec(E )=E_(0)xhat(i)`. Consider an imaginary cubical volume of edge a with its parallel to the axes of coordinates. The charge inside this volume will be
A. zero
B. `epsilon_(0)E_(0)a^(3)`
C. `1/(epsilon_(0))E_(0)a^(3)`
D. `1/6 epsilon_(0)E_(0)a^(2)`