Wave

Step 1: Longitudinal waves are waves in which the displacement of the medium is parallel to the direction of wave propagation. Sound waves and waves in springs are examples of longitudinal waves.

Step 2: Unlike transverse waves, longitudinal waves cannot be polarized. Polarization only occurs in transverse waves where oscillations are perpendicular to the direction of propagation.

Step 3: Therefore, the correct answer is that longitudinal waves cannot be polarized.