What range of frequencies is classified as Audio Frequency (AF)?

The correct answer defines the range of audio frequencies that can typically be heard by the average human ear, which is from 20 Hz to 20 kHz (20,000 Hz). This range encompasses the frequency of sounds that are perceived as audible, including various tones and pitches in music and speech.

Audio frequencies play a crucial role in sound recording, telecommunications, and acoustics. Frequencies below 20 Hz fall into the sub-bass or infrasonic category and are generally not heard but can be felt, while frequencies above 20 kHz are classified as ultrasonic and are beyond human hearing capabilities. Recognizing these boundaries helps in understanding audio systems and sound design.

Other choices represent frequency ranges outside the limits of human hearing, which either include very low frequencies or much higher frequencies, thus reinforcing the significance of the 20 Hz to 20 kHz range in auditory perception and communication.