What do we call the distance labeled from a to b and what could we do to the note played on an instrument to change that distance?

a) from a to b is known as the wavelength and changing the pitch of the note will change its length.

b) from a to b is known as the amplitude and changing the loudness of the note will change its length.

c) from a to b is known as the wavelength and changing the amplitude of the note will change its length.

d) from a to b is known as the wave height and changing the amplitude of the note will change its length.