A beam of electrons is moving through a region of space in which there is an electric field of intensity 3.4 x 104 V/m and a magnetic field of 2.0 x 10-3 T. The electric and magnetic fields are so oriented that the beam of electrons is not deflected. The velocity of the electrons is approximately:
a) 1.7 x 107 m/s
b) 6.8 x 106 m/s
c) 3.0 x 108 m/s
d) 6.0 x 10-9 m/s