The electric field part of an electromagnetic wave in a medium is represented by $E_x=0;E_y=2.5\frac{N}{C}\cos \left[\left(2\pi X{10}^6\frac{\mathrm{rad}}{\mathrm{m}}\right)t-\left(\pi X{10}^{-2}\frac{\mathrm{rad}}{\mathrm{S}}x\right)\right];$$E_z=0$. The wave is

moving along x direction with frequency 10⁶ Hz and wavelength 200 m.

moving along x direction with frequency 10⁶ Hz and wavelength 100 m.

moving along y direction with frequency $2\pi \times {10}^6\mathrm{Hz}$ and wavelength 200 m.

moving along –x direction with frequency 10⁶ Hz and wavelength 200 m.