An Electron Enters a Region of Uniform Perpendicular and Fields

Multiple Choice

An electron enters a region of uniform perpendicular and fields.It is observed that the velocity of the electron is unaffected.A possible explanation is:

A) is parallel to and has magnitude E/B
B) is parallel to
C) is perpendicular to both and and has magnitude B/E
D) is perpendicular to both and and has magnitude E/B
E) the given situation is impossible