A charged particle with charge $$q$$ enters a region of constant, uniform and mutually orthogonal fields $$\vec{E}$$ and $$\vec{B}$$ with a velocity $$\vec{v}$$ perpendicular to both $$\vec{E}$$ and $$\vec{B}$$, and comes out without any change in magnitude or direction of $$\vec{v}$$. Then

A

$$\vec{v} = \vec{E} \times \vec{B}/B^2$$

B

$$\vec{v} = \vec{B} \times \vec{E}/B^2$$

C

$$\vec{v} = \vec{E} \times \vec{B}/E^2$$

D

$$\vec{v} = \vec{B} \times \vec{E}/E^2$$