The electric field of a plane electro magnetic wave, propagating along z-axis is given by

$\mathrm{E}=2 \sin \left(8\mathrm{\pi } \mathrm{x} {10}^{14}\mathrm{t}-\frac{8\mathrm{\pi }}{3} \mathrm{x} {10}^6\mathrm{z}\right)\mathrm{v}/\mathrm{m}$

Then average intensity of the wave is 

• A

  8.16 mW/m²

• B

  5.31 mW/m²

• C

  12.28 mW/m²

• D

  28.14 mW/m²