An electron is moving along the positive x-axis. You want to apply a magnetic field for a short time so that the electron may reverse its direction and move parallel to the negative x-axis. This can be done by applying the magnetic field along.
Electron is moving along the positive x-axis now. If the particle is moving in the direction of magnetic field, then the field does not change the direction of velocity of the electron. If we apply the magnetic field in the y-axis it can reverse the direction of velocity of the electron. And also field in z-axis also can reverse the direction of the electron. So option A and B are correct.