Abeam of light is propagating in the x direction. the electric-field vector (a) can oscillate in any arbitrary direction in space. (b) must oscillate in the z direction (c) must oscillate in the yz plane (d) must oscillate in the x direction. (e) must have a steady component in the r direction.

c

Explanation:

Given beam of light is propagating in the x direction

We know that the magnetic Field and Electric field propagates perpendicular to each other as well as the direction of the Propagation of light so the Electric field vector may either Propagate in the y-axis or z-axis. So the aptest answer is oscillation in the yz plane because y and z-axis lie on the plane.