An electromagnetic wave in vacuum has the electric and magnetic fields $$\vec{E}$$ and $$\vec{B}$$, which are always perpendicular to each other. The direction of polarization is given by $$\vec{X}$$ and that of wave propagation by $$\vec{k}$$. Then :

A

$$\vec{X}\parallel \vec{B}$$ and $$\vec{k}\parallel \vec{B} \times \vec{E}$$

B

$$\vec{X}\parallel \vec{E}$$ and $$\vec{k}\parallel \vec{E} \times \vec{B}$$

C

$$\vec{X}\parallel \vec{B}$$ and $$\vec{k}\parallel \vec{E} \times \vec{B}$$

D

$$\vec{X}\parallel \vec{E}$$ and $$\vec{k}\parallel \vec{B} \times \vec{E}$$