Among the options provided, polarization is not produced by sound waves in air. Sound waves are longitudinal waves, meaning the vibrations occur in the same direction as the wave propagation. Unlike transverse waves, such as light waves, which can be polarized, sound waves cannot exhibit polarization because they do not oscillate perpendicular to their direction of travel.

However, sound waves in air can undergo diffraction, reflection, and refraction. Diffraction refers to the bending of sound waves around obstacles or through openings. Reflection occurs when sound waves bounce off surfaces. Refraction involves the bending of sound waves as they pass from one medium to another with different acoustic properties.

Understanding these phenomena helps in various applications, from designing acoustic spaces to predicting sound behavior in different environments. Therefore, the correct answer to the question is [A] Polarization.