An electromagnetic wave of frequency $1 \times 10^{14} \, Hz$ is propagating along the $z$-axis. The amplitude of the electric field is $4 \, V/m$. If $\varepsilon_0 = 8.8 \times 10^{-12} \, C^2/N \cdot m^2$,then the average energy density of the electric field will be:

• A
  $35.2 \times 10^{-10} \, J/m^3$
• B
  $35.2 \times 10^{-11} \, J/m^3$
• C
  $35.2 \times 10^{-12} \, J/m^3$
• D
  $35.2 \times 10^{-13} \, J/m^3$