The displacement of a wave from the baseline.this affects thrloudness of sound

Amplitude is the fluctuation or displacement of a wave from its mean value. With sound waves, it is the extent to which air particles are displaced, and this amplitude of sound or sound amplitude is experienced as the loudness of sound. ... It means that maximum amount the wave varies from the baseline or equilibrium.

Explanation:

After looking on the scaleattached with the question I recognized the right answer in the first option represented above. A. BODY A COMES TO REST BODY B STARTS MOVING WITH INITIAL VELOCITY OF BODY A - is definitely the only correct answer which perfectly concides with the given task.Hope you still need the answer it because this one I gave you is really useful.