As a wave travels through a medium, it displaces particles in a direction parallel to the motion of the wave. We can conclude this is a

longitudinal wave because particle displacement is the same direction as the wave
transverse wave because the wave is troveling through a medium causing particle displacement
longitudinal wave because the wave is traveling in the same direction at all times
transverse wave because the particle motion is in the some direction as the way the wave is troveling

longitunidal wave because the particles move parallel to the direction of the wave as it travels through the medium.