A proton moving with a constant velocity passes through a region of space without any change in its velocity. If $\vec E$ and $\vec B$ represent the electric and magnetic fields respectively, then the region of space may have :
(A) E=0,B=0
(B) E=0,B≠0
(C) E≠0,B=0
(D) E≠0,B≠0
Choose the most appropriate answer from the options given below :