Answer: A. Transverse
Step-by-step explanation:
Sound is a mechanical transverse wave, it travels faster in solids than in liquids or gases. This is because the speed of the mechanical waves is determined by a relationship between the elastic properties of the medium in which they are propagated and the mass per unit volume of the medium.
In addition, the speed of sound varies with changes in the temperature of the medium. This is because an increase in temperature means that the frequency of interactions between the particles that transport the vibration increases, hence this increase in activity increases the speed.
Hence:
Sounds travels in a transverse wave