Which of the following waves cannot be polarized?

When an aeroplane attains a speed higher than the velocity of sound in air,a loud bang is heard. This is because

$A$ tuning fork makes $256$ vibrations per second in air. When the velocity of sound is $330\, m/s$,the wavelength of the tone emitted is ... $m$.

The echo of a gun shot is heard $8 \, s$ after the gun is fired. How far from the shooter is the surface that reflects the sound (in $, m$)? (Velocity of sound in air $= 350 \, m/s$)

The speed of sound in oxygen at $S.T.P.$ will be approximately: (Given,$R=8.3 \text{ J K}^{-1} \text{mol}^{-1}, \gamma=1.4$) (in $\text{ m/s}$)

What is the effect of pressure on the speed of sound in a medium,if pressure is doubled at constant temperature?