When a guitar is tuned to adjust it pitch what is it that is changed?

a) its wavelength
b) its frequency
c) its amplitude
d) its linear density

B) Its frequency

Explanation:

The pitch of sound heard depends on its frequency of the sound wave. Frequency refers to how fast the sound wave is oscillating. A high frequency sound wave has a high pitch while a low frequency sound wave has a low pitch.The faster the sound wave oscillates the higher the pitch. For instance, a guitar with a big heavy string will vibrate slowly and thus create a low pitch.