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) transverse wave because the wave is traveling through a medium causing particle displacement.

b) longitudinal wave because the wave is traveling in the same direction at all times.

c) transverse wave because the particle motion is in the same direction as the way the wave is traveling.

d) longitudinal wave because particle displacement is the same direction as the wave.