Bass control in a stereo system increases the power of
A). Low frequencies
B). High frequencies
C). Medium frequencies
D). Ultrasonic

Hint: Bass refers to tones with low frequency or range. This means that the bass controls the deep part of sound. When we want to listen to the deep sounds we have to increase the bass of the music. In the stereo we have the controller using which we are able to control which frequencies that we have to focus more.

Complete answer:
Option A, Low frequencies is the correct answer. Bass, in general, refers to the low-frequency sounds that make up music that is typically utilised as a rhythm, whereas treble refers to the higher-frequency noises that are usually the more dominant components. The tones of the bass and treble clefs indicate whether the notes are at the top or bottom of the audio spectrum.
When we increase the bass of a music using the stereo control we increase the power of the deepest part of the music and we will hear less high pitched sounds. Hence by increasing the bass we hear more of the low pitched part of the music.

Option A is the correct answer.

Note:
For musical instruments like guitar, piano etcetera the mid frequency will be higher. By changing the bass and treble we can control these mid frequencies. The mid frequencies will be reduced by increasing the bass and treble. If we have trouble listening then we have to decrease the bass and treble to hear more clearly.