To find:
Why would the voice get louder and higher?
Step-by-step explanation:
The loudness of a voice is associated with the amplitude of the wave. When the amplitude of the sound wave of a voice is increased the sound becomes louder.
And the higher pitch of the voice is due to the increase in the frequency.
Thus a voice gets louder when its amplitude is increased. And the voice gets higher when its frequency is increased.
Final answer:
Thus the correct answer is option C.