Question

What kind of waves are sound waves; standing waves, surface waves, transverse waves, or longitudinal waves?

Answer 1

The last two types of waves mentioned are correct...

Explanation:

Sound is however usually only defined to propagate as a longitudinal waves, the long, standing bar-lines... This is the case for all states of matter. Additionally it can be transmitted as a transverse wave but ONLY when passing through a solid.

Source:
https://en.wikipedia.org/wiki/Sound