The following are the characteristics of the sound:
Pitch or Frequency
Intensity or Loudness
Quality or timber
a. Pitch: The frequency of a sound wave is the parameter that ear understands as pitch. A higher frequency sound has a higher pitch, and a lower frequency sound has a lower pitch
b.Loudness: The amplitude of a sound wave determines its loudness or volume. A larger amplitude means a louder sound, and a smaller amplitude means a softer sound
c. Quality or timbre: It is the characteristics which enable us to distinguish between
Timbre is associated with the shape of sound waves or waveforms produced by them.
EXPLANATION:
Amplitude, wavelength and frequency are the chaaracteristics of sound wave.
Brightness is not the characteristic of sound wave. So option 4 is correct.