Answer:
D. Sound waves
Step-by-step explanation:
The following options are missing:
A. radio wave
B. X-rays
C. Light waves
D. Sound waves
There are two kinds of waves: longitudinal and transverse.
In longitudinal waves, the vibrations are parallel to the direction of wave travel. Examples of longitudinal waves include: sound waves and ultrasound waves.
In transverse waves, the vibrations are at right angles to the direction of wave travel. All electromagnetic waves (e.g. light waves, microwaves, radio waves and X-rays) are transverse waves.