Answer:
C. Perpendicular to one another and perpendicular to the direction of wave propagation.
Explanation:
Electromagnetic waves are the waves which arise due to vibrations of both electric and magnetic fields. In electromagnetic waves, the electric and magnetic fields are perpendicular to each other and also both the electric and magnetic fields are perpendicular to the direction of wave propagation i.e. if the wave is propagating in x-direction then electric field can be in z-direction and magnetic field can be in y-direction since all the three axes are perpendicular to each other.