Answer: The correct answer is "perpendicular".
Explanation:
In a transverse wave, the particles of the medium vibrates perpendicular to the direction of the motion of the wave.
For example, light wave.
It does not need medium to propagate. It can travel in vacuum. It travels with the speed of the light.
In a longitudinal wave, the particles of the medium vibrates parallel to the direction of the motion of the wave.
For example, sound wave.
Therefore, In a transverse wave, the motion of the disturbance is perpendicular to the wave motion.
