Consider an electromagnetic wave propa- and B = -y gating in the y direction. E- y and B 0 3. E--x and B-y 4. E - -y and B = x wave propagation 0 5. E - -z and B = a 6. E - -2 and B = -a At a point in space on the y-axis, which of the following choices for the directions of O 7. E - 2 and B=-a the electric field and the magnetic field would agree with the direction of propagation. E - -2 and B -y