The correct answer is: C. They transfer energy through a medium
There are different types of waves, depending on their medium: electromagnetic (energy is transferred through vibrations of electric and magnetic field), sound (energy is transferred through vibration of air particles), water (energy is transferred through the vibration of the water particles).
Longitudinal waves - particles vibrate parallel to the direction of wave propagation
Transverse wave -particles vibrate perpendicular to the direction of wave propagation.
