The audible range of frequency for a normal human ear is about:

The correct answer is B, 20 Hz to 20,000 Hz. This is the band of frequencies to which a healthy human ear responds, and the upper limit falls with age. Below the lower limit the sound is called infrasonic and is produced by elephants, whales and earth movements before an earthquake; above the upper limit it is called ultrasonic and is produced and heard by bats, dolphins and porpoises.

Option A, 2 Hz to 200 Hz, lies almost entirely in the infrasonic band at its lower end and cuts off ordinary speech and music at its upper end. Option C, 200 Hz to 2,00,000 Hz, wrongly extends deep into the ultrasonic range, which no human can hear. Option D, 20 Hz to 2,000 Hz, has the right starting point but an upper limit ten times too low, which would leave out most of the higher notes of music that people hear easily.