Explanation

The human audible range is conventionally 20 Hz to 20,000 Hz (20 kHz); sensitivity declines with age, especially at the upper end. Frequencies below 20 Hz are infrasound and above 20 kHz are ultrasound, both inaudible to humans. Option B (20 Hz – 20 kHz) is therefore the correct audible range, while the other options extend the upper limit far beyond human hearing.