Having established that a sound wave corresponds to pressure fluctuations in the medium, what can you conclude about the direction in which such pressure fluctuations travel?

a) the direction of motion of pressure fluctuations is independent of the direction of motion of the sound wave.
b) pressure fluctuations travel perpendicularly to the direction of propagation of the sound wave.

None of them: the direction of the pressure fluctuations is parallel to the direction of motion of the wave

Explanation:

Depending on their direction of oscillation, waves can be classified into two types:

- Transverse waves: in transverse waves, the vibrations occur in a direction perpendicular to the direction of propagation of the wave. Examples of transverse waves are electromagnetic waves

- Longitudinal waves: in longitudinal waves, the vibrations occur in a direction parallel to the direction of propagation of the wave. Examples of longitudinal waves are sound waves

As we said, sound waves are longitudinal waves, so their vibrations (which correspond to the pressure fluctuations of the medium) occur in a direction parallel to the direction of propagation of the wave.