Sounds coming from moving objects, such as the siren of an emergency vehicle, appear to change pitch as the object moves toward or away from you. Compare the wavelength of a siren based on its motion toward or away from you.
Put in order from shortest wavelength
to
longest wavelength
From these following (order these from shortest to longest wavelength):
away from you at 36 mph
away from you at 31 mph
neither toward or away from you
toward you at 47 mph
toward you at 36 mph
toward you at 3 mph